1950282 - f1tv.formula1.com - Firefox is not a supported browser

Status: ASSIGNED

(Web Compatibility :: Site Reports, defect, P1)

Description

[Raul Bucata]

Environment:
Operating system: Windows 10
Firefox version: Firefox 135.0

Steps to reproduce:

1. Navigate to: https://f1tv.formula1.com/
2. Observe

Expected Behavior:
The page loads

Actual Behavior:
Browser unsupported

Notes:

• Reproduces regardless of the status of ETP
• Reproduces in firefox-nightly, and firefox-release
• Does not reproduce in chrome

Created from https://github.com/webcompat/web-bugs/issues/149085

Comment 1

[Raul Bucata]

With chromemask, the page loads as expected

Comment 2

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - add a UA override for f1tv.formula1.com; r?denschub

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7b894a5d732f
add a UA override for f1tv.formula1.com; r=denschub,webcompat-reviewers,jrmuizel

Comment 4

[amarc]

https://hg.mozilla.org/mozilla-central/rev/7b894a5d732f

Comment 5

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - add a UA override for f1tv.formula1.com on ESR128;

Comment 6

[Phabricator Automation]

esr128 Uplift Approval Request

• User impact if declined: Users will not be able to view Formula1 TV on f1tv.formula1.com due to Firefox being blocked
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: no
• Steps to reproduce for manual QE testing: Log in with a subscription on f1tv.formula1.com and try to watch any subscription video
• Risk associated with taking this patch: Low
• Explanation of risk level: Only affects our bundled webcompat addon, and only on the Formula1 website
• String changes made/needed: none
• Is Android affected?: yes

Comment 7

[Dennis Schubert [:denschub]]

For users of the 136.0 Release version on Desktop, we're now rolling out an out-of-band update to the interventions addon, see bug 1951479. The update rule is live, and the fix will delivered in the background, usually within 24 hours, but it can sometimes take longer, depending on the client.

Comment 8

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update the webcompat addon on release to v137.6.0; r?denschub

Comment 9

[Phabricator Automation]

release Uplift Approval Request

• User impact if declined: Formula1 TV (and many other sites) will block Firefox users or have other webcompat issues.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: no
• Steps to reproduce for manual QE testing: Testing fully requires a for-pay/subscription login. One must visit f1tv.formula1.com, note there is no message that Firefox is blocked, then sign in and confirm that videos actually play without additional blocks for Firefox users..
• Risk associated with taking this patch: low
• Explanation of risk level: This only changes the webcompat addon and related linting/Fenix building code which we have reviewed and verified already.
• String changes made/needed: none
• Is Android affected?: yes

Comment 10

[Thomas Wisniewski [:twisniewski]]

It turns out that the website does some kind of Android-detection in order to block Android devices, which they do not support. Unfortunately that detection thinks Firefox on Linux is Android, and so we'll need to update our intervention to handle that case as well. I'll attach a patch shortly to address this.

Comment 11

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - fix our Formula1 intervention on Linux; r?denschub

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/58d44279a23d
fix our Formula1 intervention on Linux; r=denschub,webcompat-reviewers

Comment 13

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/58d44279a23d

Comment 14

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - fix our Formula1 intervention on Linux;

Comment 15

[Phabricator Automation]

beta Uplift Approval Request

• User impact if declined: Linux users will not be able to play videos on Formula1 TV.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: no
• Steps to reproduce for manual QE testing: Testing fully requires a for-pay/subscription login. One must visit f1tv.formula1.com, note there is no message that Firefox is blocked, then sign in and confirm that videos actually play without additional blocks for Firefox users.
• Risk associated with taking this patch: Low
• Explanation of risk level: This only changes the webcompat addon and related linting/Fenix building code which we have reviewed and verified already.
• String changes made/needed: no
• Is Android affected?: yes

Comment 16

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/f0246cfee035

Comment 17

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-esr128/rev/980604e33c4a

Comment 18

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-release/rev/19e4f007176e

Comment 19

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9469616 [details]
Bug 1950282 - add a UA override for f1tv.formula1.com on ESR128;

Clearing the ESR128 approval flag to get it off the needs-uplift radar. This specific change shipped in the 128.9esr release, however.

Comment 20

[Dennis Schubert [:denschub]]

Mass-assigning diagnosis-team to webcompat for "Firefox is not supported" bugs that don't already have a team assigned. This action is done by a script. For your convenience, feel free to filter your bugmail with 559a9604-41ec-11f0-9ec6-f3f21dcd7cf2.

Comment 21

[Dennis Schubert [:denschub]]

Seems like this is happening again - I got a report from a Chrome Mask user, and Ksenia noticed a spike on the new dashboard as well. We still ship our intervention, but it seems to no longer work. Neither does Chrome Mask, so we need to re-investigate here. Putting this back into needsdiagnosis for now.

Comment 22

[Jeff Muizelaar [:jrmuizel]]

Here's how the UA detection is happening:

function Xe() {
  var e = navigator.userAgent.toLowerCase();
  if (typeof InstallTrigger != "undefined" || e.includes("gecko/") && !e.includes("like gecko") || window.mozInnerScreenX !== undefined || typeof CSS != "undefined" && CSS.supports && CSS.supports("-moz-appearance", "none")) {
    return "Firefox";
  } else if (e.includes("edg/") || e.includes("edge/")) {
    return "Edge";
  } else if (window.opr && window.opr.addons || window.opera || e.includes(" opr/")) {
    return "Opera";
  } else if (!e.includes("safari") || e.includes("chrome") || e.includes("chromium") || !/constructor/i.test(window.HTMLElement) && (!window.safari || typeof safari != "undefined" && window.safari.pushNotification).toString() !== "[object SafariRemoteNotification]") {
    if (window.chrome && (window.chrome.webstore || window.chrome.runtime) || e.includes("chrome/")) {
      return "Chrome";
    } else if (document.documentMode) {
      return "IE";
    } else {
      return "Unknown";
    }
  } else {
    return "Safari";
  }
}

Comment 23

[Jeff Muizelaar [:jrmuizel]]

Specifically it looks like window.mozInnerScreenX !== undefined is true and typeof CSS != "undefined" && CSS.supports && CSS.supports("-moz-appearance", "none") is true

Comment 24

[Jeff Muizelaar [:jrmuizel]]

Tom, how easy it to make those tests fail with an intervention?

Comment 25

[Thomas Wisniewski [:twisniewski]]

For reference, this was their code at this point (note they are sniffing for the Gecko/version hint in our current UA override):

        var Xe = function () {
          var e = navigator.userAgent.toLowerCase();
          return 'undefined' != typeof InstallTrigger ||
          e.includes('gecko/') &&
          !e.includes('like gecko') ||
          void 0 !== window.mozInnerScreenX ||
          'undefined' != typeof CSS &&
          CSS.supports &&
          CSS.supports('-moz-appearance', 'none') ? 'Firefox' : e.includes('edg/') ||
          e.includes('edge/') ? 'Edge' : window.opr &&
          window.opr.addons ||
          window.opera ||
          e.includes(' opr/') ? 'Opera' : !e.includes('safari') ||
          e.includes('chrome') ||
          e.includes('chromium') ||
          !/constructor/i.test(window.HTMLElement) &&
          '[object SafariRemoteNotification]' !== (
            !window.safari ||
            'undefined' != typeof safari &&
            window.safari.pushNotification
          ).toString() ? window.chrome &&
          (window.chrome.webstore || window.chrome.runtime) ||
          e.includes('chrome/') ? 'Chrome' : document.documentMode ? 'IE' : 'Unknown' : 'Safari'
        },

I have an patch with an update up now.

Comment 26

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com; r?denschub

Comment 27

[Dennis Schubert [:denschub]]

Let's temporarily hold off landing this - we're investigating a potentially severe memory leak in bug 1992579 that we want to understand first. If the leak is affecting the majority of users, shipping an updated intervention might do more harm than good, because the leak looks like it's in the range of OOM kills.

Comment 28

[Dennis Schubert [:denschub]]

Ah nevermind - I should read Slack. The significant memory increase was due to DevTools - so disregard comment 27.

Comment 29

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/088127cb9da8
https://hg.mozilla.org/integration/autoland/rev/30d4bf42a6c9
update our webcompat intervention for f1tv.formula1.com; r=denschub,webcompat-reviewers

Comment 30

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com;

Comment 31

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com;

Comment 32

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined: Users will not be able to watch races on Formula1 TV.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: Visit f1tv.formula1.com.
  Verify that the page does not show an "unsupported browser" message.
  Ideally, log in with a paid account and verify that videos are viewable.
• Risk associated with taking this patch: low
• Explanation of risk level: This only affects our webcompat addon on the Formula1 TV site, which is blocking us anyway, so things can't get much worse for our users. There is a potential memory leak on the site, but we could not reproduce it yet in our testing.
• String changes made/needed: none
• Is Android affected?: yes

Comment 33

[Phabricator Automation]

firefox-release Uplift Approval Request

• User impact if declined: Users will not be able to watch races on Formula1 TV.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: Visit f1tv.formula1.com.
  Verify that the page does not show an "unsupported browser" message.
  Ideally, log in with a paid account and verify that videos are viewable.
• Risk associated with taking this patch: low
• Explanation of risk level: This only affects our webcompat addon on the Formula1 TV site, which is blocking us anyway, so things can't get much worse for our users. There is a potential memory leak on the site, but we could not reproduce it yet in our testing.
• String changes made/needed: none
• Is Android affected?: yes

Comment 34

[Phabricator Automation]

firefox-esr140 Uplift Approval Request

• User impact if declined: Users will not be able to watch races on Formula1 TV.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: Visit f1tv.formula1.com.
  Verify that the page does not show an "unsupported browser" message.
  Ideally, log in with a paid account and verify that videos are viewable.
• Risk associated with taking this patch: low
• Explanation of risk level: This only affects our webcompat addon on the Formula1 TV site, which is blocking us anyway, so things can't get much worse for our users. There is a potential memory leak on the site, but we could not reproduce it yet in our testing.
• String changes made/needed: none
• Is Android affected?: yes

Comment 35

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com;

Comment 36

[SimonB]

(In reply to Dennis Schubert [:denschub] from comment #21)

Seems like this is happening again - I got a report from a Chrome Mask user, and Ksenia noticed a spike on the new dashboard as well. We still ship our intervention, but it seems to no longer work. Neither does Chrome Mask, so we need to re-investigate here. Putting this back into needsdiagnosis for now.

I have been using Firefox for a paid account all this year until today - ChromeMask and UserAgent are not solving this. I have installed Brave for the first time to watch as it is urgent.

Comment 37

[amarc]

https://hg.mozilla.org/mozilla-central/rev/30d4bf42a6c9

Comment 38

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/d7a38619faa9
https://hg.mozilla.org/releases/mozilla-beta/rev/57b7a8d86cac

Comment 39

[Rares Doghi, Desktop QA]

This issue is verified as fixed in our latest Nightly 147.0a1 (2025-11-21), however after creating a free account I couldnt find any videos, ads or even trailers I could play from this website. I tried different areas from this site as well and the unsupported browser message is no longer displayed.

Comment 40

[Rares Doghi, Desktop QA]

This issue is verified as fixed in our latest Beta 146.0b6.

Comment 41

[jasper]

With a paid account, I no longer get the unsupported browser message and can play videos (on Nightly 147.0a1).

Comment 42

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/4a0a11212a20
https://hg.mozilla.org/releases/mozilla-release/rev/5bc6858de618

Comment 43

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-esr140/rev/5482ec9c77c3

Comment 44

[Rares Doghi, Desktop QA]

This issue is verified as fixed in Both ESR 140.6.0esr as well as our latest Release candidate 145.0.2, @Donal should we update the flags for release as well ?

Comment 45

[Donal Meehan [:dmeehan]]

(In reply to Rares Doghi, Desktop QA from comment #44)

This issue is verified as fixed in Both ESR 140.6.0esr as well as our latest Release candidate 145.0.2, @Donal should we update the flags for release as well ?

Yes, I don't see a problem with that

Comment 46

[Rares Doghi, Desktop QA]

Verified as fixed in our latest Release 145.0.2, however the main status flag for this issue is still "Assigned" instead of Resolved Fixed, please also note that for Esr 128 this issue is not fixed, @Thomas can you update the main status flag ? also should we change the old esr 128 flag back to affected or wont fix ?

Comment 47

[Thomas Wisniewski [:twisniewski]]

For internal tracking purposes, we leave issues open when they aren't fully fixed (by the site in this case), but only have a webcompat intervention shipped with works around the issue. But we should make sure the version-specific flags are set, yes. I will make a patch for ESR128 in case we want to fix it there as well (since we did before).

Comment 48

[Donal Meehan [:dmeehan]]

ESr128 is end of life after we shipped ESR140.3

Comment 49

[Rares Doghi, Desktop QA]

Got it, I will update the remaining tags for this issue. Thank you both.

Comment 50

[Thomas Wisniewski [:twisniewski]]

It looks like they've blocked us again. They're checking userAgentData, and especially checking the platformVersion on Windows. I can adjust our intervention. Patching incoming.

Comment 51

[Jeff Muizelaar [:jrmuizel]]

Looks like they're using https://github.com/faisalman/ua-parser-js for UA parsing. Not sure what it doesn't like yet.

Comment 52

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com; r?denschub

Comment 53

[Jeff Muizelaar [:jrmuizel]]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #51)

Looks like they're using https://github.com/faisalman/ua-parser-js for UA parsing. Not sure what it doesn't like yet.

Actually, this looks like it's used for a different part.

Here's the update to UA code posted in comment 25:

a = function () {
          var e = navigator.userAgent.toLowerCase();
          return 'undefined' != typeof InstallTrigger ||
          e.includes('gecko/') &&
          !e.includes('like gecko') ||
          void 0 !== window.mozInnerScreenX ||
          'undefined' != typeof CSS &&
          CSS.supports &&
          CSS.supports('-moz-appearance', 'none') ? 'Firefox' : void 0 !== navigator.userAgentData ||
          !('MozAppearance' in document.documentElement.style) &&
          'undefined' == typeof CSSMozDocumentRule ? e.includes('edg/') ||
          e.includes('edge/') ? 'Edge' : window.opr &&
          window.opr.addons ||
          window.opera ||
          e.includes(' opr/') ? 'Opera' : !e.includes('safari') ||
          e.includes('chrome') ||
          e.includes('chromium') ||
          !/constructor/i.test(window.HTMLElement) &&
          '[object SafariRemoteNotification]' !== (
            !window.safari ||
            'undefined' != typeof safari &&
            window.safari.pushNotification
          ).toString() ? window.chrome &&
          (window.chrome.webstore || window.chrome.runtime) ||
          e.includes('chrome/') ? 'Chrome' : document.documentMode ? 'IE' : 'Unknown' : 'Safari' : 'Firefox'
        }

Comment 54

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/6a1e134a7f35
https://hg.mozilla.org/integration/autoland/rev/d89213e2f40a
update our webcompat intervention for f1tv.formula1.com; r=webcompat-reviewers,ksenia

Comment 55

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/d89213e2f40a

Comment 56

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com;

Comment 57

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com;

Comment 58

[Thomas Wisniewski [:twisniewski]]

Attachment: Bug 1950282 - update our webcompat intervention for f1tv.formula1.com;

Comment 59

[Phabricator Automation]

firefox-beta Uplift Approval Request

• User impact if declined: Formula1 TV users will be blocked on Firefox, and not be able to view videos on their paid F1TV accounts.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: 1 .Visit https://f1tv.formula1.com/

2. Confirm that "This browser is not supported" is not shown.
3. Log in, and confirm that you can play a video only viewable with a paid account.

• Risk associated with taking this patch: low
• Explanation of risk level: The site is already essentially broken, so we can't make it much worse. This also is designed to only impact our webcompat addon, and only f1tv specifically.
• String changes made/needed: none
• Is Android affected?: yes

Comment 60

[Phabricator Automation]

firefox-release Uplift Approval Request

• User impact if declined: Formula1 TV users will be blocked on Firefox, and not be able to view videos on their paid F1TV accounts.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: 1 .Visit https://f1tv.formula1.com/

2. Confirm that "This browser is not supported" is not shown.
3. Log in, and confirm that you can play a video only viewable with a paid account.

• Risk associated with taking this patch: low
• Explanation of risk level: The site is already essentially broken, so we can't make it much worse. This also is designed to only impact our webcompat addon, and only f1tv specifically.
• String changes made/needed: none
• Is Android affected?: yes

Comment 61

[Phabricator Automation]

firefox-esr140 Uplift Approval Request

• User impact if declined: Formula1 TV users will be blocked on Firefox, and not be able to view videos on their paid F1TV accounts.
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: yes
• Steps to reproduce for manual QE testing: 1 .Visit https://f1tv.formula1.com/

2. Confirm that "This browser is not supported" is not shown.
3. Log in, and confirm that you can play a video only viewable with a paid account.

• Risk associated with taking this patch: low
• Explanation of risk level: The site is already essentially broken, so we can't make it much worse. This also is designed to only impact our webcompat addon, and only f1tv specifically.
• String changes made/needed: none
• Is Android affected?: no

Comment 62

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/33ce5d8fffa0
https://hg.mozilla.org/releases/mozilla-beta/rev/c99ba2375421

Comment 63

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-esr140/rev/c7a6bdb65004

Comment 64

[Pulsebot]

https://github.com/mozilla-firefox/firefox/commit/8dcb9ed3018e
https://hg.mozilla.org/releases/mozilla-release/rev/2c18ee925d58

Comment 65

[Rares Doghi, Desktop QA]

This issue is Verified as fixed in our latest ESR 140.8.0esr, Release 147.0.4 as well as Beta 148.0b16

Comment 66

[Mira Lobontiu (Android QA)]

Verified that "This browser is not supported" is not displayed on the Firefox for Android 147.0.4, Beta 148.0b15, and Nightly 149.0a1 with a Motorola Moto G30 (Android 12), and a Pixel 6 (Android 16).