Compare / browsers

WebKit vs the Safari it claims to be

Playwright's WebKit 26.4 sends a Mac Safari 26.4 user agent, but reports Linux x86_64, sets navigator.webdriver, offers only HTTP/1.1, renders with Linux fonts and has no WebGPU — while already exposing CSS from Safari 27.0. What it is good for, and every place a page can see it isn't Safari on a Mac or an iPhone.

WebKit

WebKit on the fleet is the WebKit build that ships with Playwright, compiled for Linux — browser.version() 26.4 on 2026-11-13. Its user agent says it is Safari 26.4 on a Mac. This page puts the two side by side: what the user agent and Playwright's Desktop Safari and iPhone 15 descriptors claim, what a page and the network actually measure, and what Apple's release notes say Safari itself ships. It is measurement documentation for testers and scrapers, not a guide to hiding any of it. The comparison with Chromium is on WebKit vs Chromium.

What it claims, what it is

	What the user agent claims	What the fleet's WebKit measures
Browser version	`Version/26.4 Safari/605.1.15` — Safari 26.4 (Safari 26.4 notes (2026-03-24)). Safari is at 27.2 since 2026-10-26 (Safari 27.2 notes (2026-10-26)).	A WebKit build between releases: it has 26.5's `:open`, `Origin` and `ToggleEvent.source` (26.5 (2026-05-11)) and 27.0's `width: stretch`, `:heading`, `revert-rule`, `ReadableStream.from()`, `appearance: base-select`, `overflow-anchor` and WebAssembly JSPI (Safari 27.0 notes (2026-09-17)), and still the `flow-tolerance` name that 27.2 renamed to `fit-tolerance` (measured).
Operating system	`Macintosh; Intel Mac OS X 10_15_7` — a frozen string; Safari on macOS freezes the OS version (Safari 26.0 notes (2025-09-15)).	`navigator.platform` `Linux x86_64`; `navigator.appVersion` repeats the Mac string (measured).
Automation	—	`navigator.webdriver` is `true`, headful and headless; bot.sannysoft.com fails "WebDriver (New)" and "Chrome (New)" of 57 checks (measured).
Vendor and client hints	`navigator.vendor` "Apple Computer, Inc.", no `navigator.userAgentData`.	The same — consistent with WebKit (measured).
Graphics	WebGL vendor "Apple Inc.", renderer "Apple GPU", WebGL 2.0.	Exactly these strings on a server with no GPU, so they are fixed values, not the hardware (measured). No WebGPU (`navigator.gpu` absent), which Safari 26.0 ships on macOS, iOS, iPadOS and visionOS (Safari 26.0 notes (2025-09-15)).
Network	An Apple browser. caniuse (checked 2026-11-13) lists HTTP/2 in Safari from 11 on macOS and 9 on iOS.	TLS ALPN offers only `http/1.1`, `http/1.0`, so every HTTPS site gets HTTP/1.1; JA4 `t13d2913h1_723694b0fccc_5671b5df5029` (29 ciphers, 13 extensions). Request header order: Accept, User-Agent, Accept-Encoding, Accept-Language, Connection, Host, Sec-Fetch-Dest/Mode/Site (measured).
Fonts	A Mac's fonts.	None of `-apple-system`, SF Pro, Helvetica Neue, Menlo, Monaco, Lucida Grande, Geneva, Avenir, Futura, Georgia, Verdana, PingFang SC, Hiragino Sans or Apple Color Emoji. Present: Liberation Sans/Serif/Mono, Noto Sans, Noto Color Emoji, FreeSans; Helvetica and Arial render with Liberation Sans's metrics, Times with Liberation Serif's, Courier with Liberation Mono's (measured).
Media	Native HLS: caniuse (checked 2026-11-13) lists it in Safari from 6 on macOS and 3.2 on iOS.	`canPlayType('application/vnd.apple.mpegurl')` is "" — no native HLS. H.264, HEVC, AAC, VP9, AV1 and Opus answer "probably"; `MediaSource` and `ManagedMediaSource` exist (measured).
Apple-platform APIs	Apple Pay, AirPlay, Web Push (caniuse, checked 2026-11-13: Safari 18 on macOS, 16.4 on iOS), File System WritableStream and the Digital Credentials API (both Safari 26.0 notes (2025-09-15)).	`ApplePaySession`, `-apple-pay-button-style`, the AirPlay picker, `PushManager`, `navigator.share`, `FileSystemWritableFileStream` and `DigitalCredential` are all absent; 27.0's `srgb-linear` canvas colour space too. `window.safari`, `GestureEvent` and `webkitEnterFullscreen` exist (measured).

Headful and headless are the same browser

Both report the same user agent — WebKit adds no "Headless" token — the same JA4, navigator.webdriver true, WebGL strings, canvas hash 25c86b3f, feature set and the same two sannysoft failures (measured).
The one page-visible difference: headless has outerWidth×outerHeight equal to the viewport (1280×720), headful has 38 px of window chrome (1280×758).
Headless costs one thread instead of two and launched in 0.4 s against 0.7 s in this run.

What the device descriptors change

devices['Desktop Safari'] sends the same user agent WebKit already sends and changes only the pixel ratio (2) and screen (1792×1120); the viewport stays 1280×720 (measured).
devices['iPhone 15'] sets the iPhone user agent iPhone OS 17_5 … Version/26.4 Mobile/15E148 Safari/604.1, a 393×659 viewport on a 393×852 screen, pixel ratio 3, ontouchstart, pointer: coarse and no hover (measured).
It leaves navigator.platform Linux x86_64, maxTouchPoints 0, navigator.webdriver true, no navigator.standalone, no -webkit-touch-callout, and the same HTTP/1.1, JA4, fonts and missing WebGPU (measured).
The user agent pairs iPhone OS 17_5 with Version/26.4. Apple's notes give Safari 26.0 on iOS as iPhone OS 18_6 … Version/26.0: from 26 on, iOS freezes the OS version the way macOS does (Safari 26.0 notes (2025-09-15)). So the descriptor's string is not one Safari 26 sends.
As with an iPhone descriptor on Chrome (case 02), a descriptor changes layout inputs, not the platform underneath. For a real iOS WebView, see iPhone.

What a site can use to tell it isn't Safari on a Mac or an iPhone

navigator.platform Linux x86_64 under a Macintosh or iPhone user agent.
navigator.webdriver true.
HTTP/1.1 only (ALPN without h2) and its JA4, where Safari speaks HTTP/2 — visible before any page script runs (TLS fingerprints).
No WebGPU, no native HLS, no Apple Pay, AirPlay or Push API — features the claimed version ships on Apple platforms.
Linux font metrics: no Apple system fonts, Noto Color Emoji instead of Apple Color Emoji.
A feature set that doesn't match the version in the user agent: 27.0 features under Version/26.4.
On the iPhone descriptor, also maxTouchPoints 0 with touch events, and an iOS 17 string beside a Safari 26 version.

What it is good for

Engine and layout testing: how WebKit lays out a page — anchor positioning, Grid Lanes, text-wrap: pretty, customizable <select>, scroll-driven animations — and WebKit-specific bugs, including mobile viewports with a device descriptor. It runs ahead of the Safari release its user agent names, so treat it as "WebKit trunk", not as a specific Safari version.
Not for pixel comparisons with a Mac: text renders with Linux fonts, so screenshots won't match Safari on macOS or iOS.
Not for Apple-only features: Apple Pay, AirPlay, native HLS, WebGPU and Web Push can't be tested here.
Not as a Safari visitor: every row above is readable by a site. For scraping, see WebKit vs Chromium and What a page can read about your browser.

Measured on the fleet (2026-11-13)

Two launches through the same proxy, headful (the default) and headless, probed from inside a page and via tls.peet.ws. The descriptor, font, codec, Apple-API and release-note feature rows above come from a one-off run in a third, headful session the same night (no descriptor, Desktop Safari, iPhone 15 contexts); its raw result is under descriptor_contexts below.

Launch and cost

Single run; timings depend on the proxy and on fleet load.

	WebKit headful	WebKit headless
Launch body	{"headless":false}	{"headless":true}
Threads used	2 (linux_headful)	1 (linux_headless)
Browser version	26.4	26.4
Launch request → browser ready	0.7 s	0.4 s
Playwright connect	0.1 s	0.0 s
Load example.com	1.9 s	0.5 s
Load tls.peet.ws/api/all	2.0 s	1.4 s

What the network sees

From tls.peet.ws/api/all, requested by the browser itself. JA3 hashes change between runs of the same build (GREASE), so compare JA4 and the HTTP/2 fingerprint.

	WebKit headful	WebKit headless
HTTP version	HTTP/1.1	HTTP/1.1
JA4	t13d2913h1_723694b0fccc_5671b5df5029	t13d2913h1_723694b0fccc_5671b5df5029
Peetprint hash	e2a4f6ec1c75767498bc87d934bfccec	e2a4f6ec1c75767498bc87d934bfccec
Cipher suites / extensions	29 / 13	29 / 13

What page scripts see

Read with page.evaluate on example.com. Cores and memory are the server's and vary between fleet nodes.

	WebKit headful	WebKit headless
navigator.userAgent	Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15	Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15
navigator.platform / vendor	Linux x86_64 / Apple Computer, Inc.	Linux x86_64 / Apple Computer, Inc.
Languages	en-US	en-US
Timezone / locale	UTC / en-US	UTC / en-US
Screen (w×h×availW×availH×depth)	1280x720x1280x720x24	1280x720x1280x720x24
Window outer / inner / DPR	1280x758 / 1280x720 / 1	1280x720 / 1280x720 / 1
hardwareConcurrency / deviceMemory	8 / —	8 / —
WebGL vendor	Apple Inc.	Apple Inc.
WebGL renderer	Apple GPU	Apple GPU
WebGL version	WebGL 2.0	WebGL 2.0
WebGPU (navigator.gpu)	no	no
Canvas hash	25c86b3f	25c86b3f
navigator.webdriver	yes	yes
window.chrome / navigator.connection	no / no	no / no
Plugins / PDF viewer	5 / yes	5 / yes
Notification.permission / permissions.query	default / prompt	default / prompt

Web platform features

Presence probes; a user agent that claims one version while exposing another's features is a detectable inconsistency.

	WebKit headful	WebKit headless
`Iterator.prototype.includes` (new in Chrome 154)	no	no
`FontFace.width` (new in Chrome 154)	yes	yes
CSS `text-decoration-inset` (Chrome 157)	no	no
`Iterator.prototype.join` (Chrome 153)	no	no
`Iterator.zip` (Chrome 153)	no	no
CSS `scroll-axis-lock` (Chrome 153)	no	no
`<camera>` element (Chrome 153)	no	no
`document.requestStorageAccessFor` (deprecated in 153)	no	no
Topics API (`document.browsingTopics`)	no	no
Protected Audience (`navigator.joinAdInterestGroup`)	no	no
Shared Storage (`window.sharedStorage`)	no	no
Attribution Reporting (`window.attributionReporting`)	no	no
Private Aggregation	no	no
WebHID (`navigator.hid`)	no	no
CSS `margin-trim` (Chrome 155)	yes	yes
CSS `text-decoration-skip-spaces` (Chrome 155)	no	no
CSS `corner` shorthand (listed for Chrome 160)	no	no
CSS `symbols()` (Chrome 155)	no	no
`Element.streamAppendHTML` (Chrome 157)	no	no
`WebTransport.reliability` (on stable from Chrome 157; listed for 158)	yes	yes
`window.maximize()` — Additional Windowing Controls (Chrome 155)	no	no
Canvas `srgb-linear` colour space (on stable from Chrome 157)	no	no
Permission policy `media-playback-while-not-visible` (Chrome 155)	no	no
CSS `random()` (Chrome 156)	yes	yes
CSS `scroll-snap-type: pair` (Chrome 156)	no	no
Fenced frames (`window.fence`)	no	no
`rel=compression-dictionary` (Chrome 156 updates)	no	no

bot.sannysoft.com

The classic headless-detection test page; what it marks red.

	WebKit headful	WebKit headless
Checks / failed	57 / 2	57 / 2
Failed checks	WebDriver (New), Chrome (New)	WebDriver (New), Chrome (New)

A plain-HTTP URL (http://ip-api.com/json)

Chrome 154 warns before loading insecure HTTP by default — does that reach an automated session?

	WebKit headful	WebKit headless
Final URL	http://ip-api.com/json/?fields=status	http://ip-api.com/json/?fields=status
HTTP status	200	200
Content loaded / warning page first	yes / no	yes / no

Playwright over the remote connection

Which client features work on this side.

	WebKit headful	WebKit headless
page.evaluate runs in the page's own world	yes	yes
addInitScript visible to page scripts	yes	yes
Console events	yes	yes
Request interception (page.route)	yes	yes
Screenshot	yes	yes
PDF	no — Error: page.pdf: PDF generation is only supported for Headless Chromium	no — Error: page.pdf: PDF generation is only supported for Headless Chromium
Mobile device emulation	yes	yes
Tracing	yes	yes

Rows where the two sides differ are highlighted. IP addresses are replaced with placeholders (203.0.113.x). The probe is compare/probe.mjs in our repository; the raw result is below.

Raw output

{
  "ran_at": "2026-11-13T02:04:40.661Z",
  "sides": [
    {
      "label": "WebKit headful",
      "engine": "webkit",
      "body": {
        "headless": false
      },
      "launch": {
        "browser": "webkit",
        "resource_class": "linux_headful",
        "weight": 2,
        "launch_ms": 670,
        "connect_ms": 150,
        "example_ms": 1891,
        "peet_ms": 2038
      },
      "network": {
        "http_version": "HTTP/1.1",
        "ja4": "t13d2913h1_723694b0fccc_5671b5df5029",
        "ja3_hash": "2cbcec37dfff29e4c6a34dd35ebe1d70",
        "peetprint_hash": "e2a4f6ec1c75767498bc87d934bfccec",
        "ciphers": 29,
        "extensions": 13,
        "header_order": null
      },
      "page": {
        "user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15",
        "platform": "Linux x86_64",
        "vendor": "Apple Computer, Inc.",
        "languages": [
          "en-US"
        ],
        "hardware_concurrency": 8,
        "device_memory": null,
        "max_touch_points": 0,
        "webdriver": true,
        "plugins": 5,
        "pdf_viewer": true,
        "ua_data": null,
        "screen": "1280x720x1280x720x24",
        "window": {
          "outer": "1280x758",
          "inner": "1280x720",
          "dpr": 1
        },
        "timezone": "UTC",
        "locale": "en-US",
        "webgl": {
          "vendor": "Apple Inc.",
          "renderer": "Apple GPU",
          "version": "WebGL 2.0"
        },
        "canvas_hash": "25c86b3f",
        "webgpu": false,
        "chrome_object": false,
        "chrome_runtime": false,
        "notification_permission": "default",
        "notification_query": "prompt",
        "has_focus": true,
        "connection_api": false,
        "stack_read_by_debugger": false,
        "features": {
          "iterator_includes": false,
          "iterator_join": false,
          "iterator_zip": false,
          "fontface_width": true,
          "css_text_decoration_inset": false,
          "css_scroll_axis_lock": false,
          "websocket_options_bag": null,
          "camera_element": false,
          "topics_api": false,
          "protected_audience": false,
          "shared_storage": false,
          "attribution_reporting": false,
          "request_storage_access_for": false,
          "webhid": false,
          "private_aggregation": false,
          "css_margin_trim": true,
          "css_text_decoration_skip_spaces": false,
          "css_corner_shorthand": false,
          "css_symbols": false,
          "stream_append_html": false,
          "webtransport_reliability": true,
          "window_maximize": false,
          "canvas_srgb_linear": false,
          "policy_media_playback_while_not_visible": false,
          "css_random": true,
          "css_scroll_snap_pair": false,
          "fenced_frames": false,
          "compression_dictionary": false
        }
      },
      "page_main_world": null,
      "sannysoft": {
        "checks": 57,
        "failed": 2,
        "failed_names": [
          "WebDriver (New)",
          "Chrome (New)"
        ],
        "passed": 29
      },
      "plain_http": {
        "final_url": "http://ip-api.com/json/?fields=status",
        "status": 200,
        "title": "",
        "loaded": true,
        "warning_page": false,
        "page_text": "{\"status\":\"success\"}"
      },
      "playwright": {
        "evaluate_in_main_world": true,
        "console_events": true,
        "init_script": true,
        "route": true,
        "screenshot": true,
        "pdf": false,
        "pdf_error": "Error: page.pdf: PDF generation is only supported for Headless Chromium",
        "mobile_emulation": true,
        "tracing": true
      },
      "browser_version": "26.4"
    },
    {
      "label": "WebKit headless",
      "engine": "webkit",
      "body": {
        "headless": true
      },
      "launch": {
        "browser": "webkit",
        "resource_class": "linux_headless",
        "weight": 1,
        "launch_ms": 442,
        "connect_ms": 17,
        "example_ms": 466,
        "peet_ms": 1402
      },
      "network": {
        "http_version": "HTTP/1.1",
        "ja4": "t13d2913h1_723694b0fccc_5671b5df5029",
        "ja3_hash": "2cbcec37dfff29e4c6a34dd35ebe1d70",
        "peetprint_hash": "e2a4f6ec1c75767498bc87d934bfccec",
        "ciphers": 29,
        "extensions": 13,
        "header_order": null
      },
      "page": {
        "user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15",
        "platform": "Linux x86_64",
        "vendor": "Apple Computer, Inc.",
        "languages": [
          "en-US"
        ],
        "hardware_concurrency": 8,
        "device_memory": null,
        "max_touch_points": 0,
        "webdriver": true,
        "plugins": 5,
        "pdf_viewer": true,
        "ua_data": null,
        "screen": "1280x720x1280x720x24",
        "window": {
          "outer": "1280x720",
          "inner": "1280x720",
          "dpr": 1
        },
        "timezone": "UTC",
        "locale": "en-US",
        "webgl": {
          "vendor": "Apple Inc.",
          "renderer": "Apple GPU",
          "version": "WebGL 2.0"
        },
        "canvas_hash": "25c86b3f",
        "webgpu": false,
        "chrome_object": false,
        "chrome_runtime": false,
        "notification_permission": "default",
        "notification_query": "prompt",
        "has_focus": true,
        "connection_api": false,
        "stack_read_by_debugger": false,
        "features": {
          "iterator_includes": false,
          "iterator_join": false,
          "iterator_zip": false,
          "fontface_width": true,
          "css_text_decoration_inset": false,
          "css_scroll_axis_lock": false,
          "websocket_options_bag": null,
          "camera_element": false,
          "topics_api": false,
          "protected_audience": false,
          "shared_storage": false,
          "attribution_reporting": false,
          "request_storage_access_for": false,
          "webhid": false,
          "private_aggregation": false,
          "css_margin_trim": true,
          "css_text_decoration_skip_spaces": false,
          "css_corner_shorthand": false,
          "css_symbols": false,
          "stream_append_html": false,
          "webtransport_reliability": true,
          "window_maximize": false,
          "canvas_srgb_linear": false,
          "policy_media_playback_while_not_visible": false,
          "css_random": true,
          "css_scroll_snap_pair": false,
          "fenced_frames": false,
          "compression_dictionary": false
        }
      },
      "page_main_world": null,
      "sannysoft": {
        "checks": 57,
        "failed": 2,
        "failed_names": [
          "WebDriver (New)",
          "Chrome (New)"
        ],
        "passed": 29
      },
      "plain_http": {
        "final_url": "http://ip-api.com/json/?fields=status",
        "status": 200,
        "title": "",
        "loaded": true,
        "warning_page": false,
        "page_text": "{\"status\":\"success\"}"
      },
      "playwright": {
        "evaluate_in_main_world": true,
        "console_events": true,
        "init_script": true,
        "route": true,
        "screenshot": true,
        "pdf": false,
        "pdf_error": "Error: page.pdf: PDF generation is only supported for Headless Chromium",
        "mobile_emulation": true,
        "tracing": true
      },
      "browser_version": "26.4"
    }
  ],
  "descriptor_contexts": {
    "note": "One-off run in one headful WebKit session, three contexts: no descriptor, Playwright devices[\"Desktop Safari\"], devices[\"iPhone 15\"]. Network from tls.peet.ws/api/all; the rest read with page.evaluate on example.com. Fonts: a family is present when \"<family>, serif\" or \"<family>, Liberation Mono\" measures differently from the fallback alone (width = 48px test string). Features: presence probes for items from WebKit's Safari 26.0–27.2 release notes.",
    "ran_at": "2026-11-13T02:07:50.847Z",
    "body": {
      "headless": false
    },
    "browser_version": "26.4",
    "contexts": {
      "no descriptor": {
        "network": {
          "http_version": "HTTP/1.1",
          "ja4": "t13d2913h1_723694b0fccc_5671b5df5029",
          "alpn": [
            "http/1.1",
            "http/1.0"
          ],
          "http1_headers": [
            "Accept",
            "User-Agent",
            "Accept-Encoding",
            "Accept-Language",
            "Connection",
            "Host",
            "Sec-Fetch-Dest",
            "Sec-Fetch-Mode",
            "Sec-Fetch-Site"
          ],
          "user_agent_header": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15"
        },
        "identity": {
          "user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15",
          "app_version": "5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.4 Safari/605.1.15",
          "platform": "Linux x86_64",
          "vendor": "Apple Computer, Inc.",
          "ua_data": false,
          "webdriver": true,
          "max_touch_points": 0,
          "ontouchstart": false,
          "standalone": "absent",
          "pointer_coarse": false,
          "hover": true,
          "screen": "1280x720",
          "viewport": "1280x720",
          "dpr": 1,
          "outer": "1280x758",
          "languages": [
            "en-US"
          ],
          "timezone": "UTC",
          "plugins": [
            "PDF Viewer",
            "Chrome PDF Viewer",
            "Chromium PDF Viewer",
            "Microsoft Edge PDF Viewer",
            "WebKit built-in PDF"
          ],
          "speech_voices": 4
        },
        "apple_apis": {
          "window_safari": "object",
          "apple_pay_session": "undefined",
          "apple_pay_css": false,
          "webkit_message_handlers": false,
          "gesture_event": "function",
          "airplay_event": "undefined",
          "airplay_picker": "undefined",
          "webkit_enter_fullscreen": "function",
          "touch_callout_css": false,
          "managed_media_source": "function",
          "media_source": "function",
          "navigator_share": "undefined",
          "push_manager": "undefined",
          "digital_credential": "undefined",
          "webgpu": false
        },
        "codecs": {
          "hls_native": "no",
          "h264_mp4": "probably",
          "hevc_mp4": "probably",
          "aac_mp4": "probably",
          "vp9_webm": "probably",
          "av1_mp4": "probably",
          "opus_ogg": "probably",
          "flac": "maybe",
          "mse_h264": true,
          "mse_vp9": true
        },
        "fonts_base": {
          "monospace": 692.84,
          "serif": 663.99,
          "sans-serif": 692.84,
          "liberation_mono": 576.09,
          "missing": 663.99
        },
        "fonts": {
          "-apple-system": {
            "present": false,
            "width": 576.09
          },
          "BlinkMacSystemFont": {
            "present": false,
            "width": 576.09
          },
          "system-ui": {
            "present": true,
            "width": 692.84
          },
          "SF Pro": {
            "present": false,
            "width": 576.09
          },
          "SF Pro Text": {
            "present": false,
            "width": 576.09
          },
          "Helvetica Neue": {
            "present": false,
            "width": 576.09
          },
          "Helvetica": {
            "present": true,
            "width": 691.29
          },
          "Arial": {
            "present": true,
            "width": 691.29
          },
          "Times": {
            "present": true,
            "width": 662.86
          },
          "Times New Roman": {
            "present": true,
            "width": 662.86
          },
          "Courier": {
            "present": true,
            "width": 576.09
          },
          "Courier New": {
            "present": true,
            "width": 576.09
          },
          "Georgia": {
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        },
        "codecs": {
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          "h264_mp4": "probably",
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      },
      "iPhone 15": {
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          "alpn": [
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            "Accept-Encoding",
            "Accept-Language",
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          "vendor": "Apple Computer, Inc.",
          "ua_data": false,
          "webdriver": true,
          "max_touch_points": 0,
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          "hover": false,
          "screen": "393x852",
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          ],
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          ],
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        },
        "apple_apis": {
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          "navigator_share": "undefined",
          "push_manager": "undefined",
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        },
        "codecs": {
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          "h264_mp4": "probably",
          "hevc_mp4": "probably",
          "aac_mp4": "probably",
          "vp9_webm": "probably",
          "av1_mp4": "probably",
          "opus_ogg": "probably",
          "flac": "maybe",
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          },
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          },
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          },
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          },
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          }
        },
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          "regexp_modifiers": true,
          "digital_credentials": false,
          "scoped_custom_element_registry": false,
          "field_sizing": true,
          "css_random": true,
          "sibling_index": true,
          "button_command": true,
          "navigation_api": true,
          "math_sum_precise": true,
          "map_get_or_insert": true,
          "scrollbar_color": true,
          "caret_position_from_point": true,
          "lcp_entries": true,
          "grid_lanes": true,
          "iterator_concat": true,
          "webtransport": true,
          "math_depth": true,
          "open_pseudo": true,
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          "stretch_keyword": true,
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          "revert_rule": true,
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          "overflow_anchor": true,
          "canvas_srgb_linear": false,
          "wasm_jspi": true,
          "fit_tolerance": false,
          "flow_tolerance": true,
          "field_content_pseudo": false,
          "video_encoder": true
        }
      }
    }
  }
}

Bottom line

Playwright's WebKit is the WebKit engine on Linux with a Mac Safari user agent: its layout and CSS are WebKit's — newer than the version it names — while its platform, webdriver flag, HTTP version, fonts, media and Apple-only APIs are not Safari's.

Use it to check how the engine behind Apple's browser renders a page; don't read its results as what Safari on a Mac or an iPhone would show a site or a user.