[Tracking Requested - why for this release]:

• Central-as-beta simulation.
• How to run these simulations.

Failure log:

[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: operation empty() 
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - TEST-UNEXPECTED-FAIL | /selection/idlharness.window.html | Selection interface: operation getComposedRanges(ShadowRoot...) - assert_own_property: interface prototype object missing non-static operation expected property "getComposedRanges" missing
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - IdlInterface.prototype.test_member_operation/<@http://web-platform.test:8000/resources/idlharness.js:2304:32
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - Test.prototype.step@http://web-platform.test:8000/resources/testharness.js:2622:25
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - IdlInterface.prototype.test_member_operation@http://web-platform.test:8000/resources/idlharness.js:2257:12
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - IdlInterface.prototype.test_members@http://web-platform.test:8000/resources/idlharness.js:2721:26
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - IdlInterface.prototype.test@http://web-platform.test:8000/resources/idlharness.js:1442:10
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - IdlArray.prototype.test@http://web-platform.test:8000/resources/idlharness.js:748:28
[task 2024-03-26T14:22:27.364Z] 14:22:27     INFO - idl_test/</<@http://web-platform.test:8000/resources/idlharness.js:3529:31
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - ...................
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "type" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "direction" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "getRangeAt(unsigned long)" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: calling getRangeAt(unsigned long) on getSelection() with too few arguments must throw TypeError 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "addRange(Range)" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: calling addRange(Range) on getSelection() with too few arguments must throw TypeError 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "removeRange(Range)" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: calling removeRange(Range) on getSelection() with too few arguments must throw TypeError 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "removeAllRanges()" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-PASS | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "empty()" with the proper type 
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - TEST-UNEXPECTED-FAIL | /selection/idlharness.window.html | Selection interface: getSelection() must inherit property "getComposedRanges(ShadowRoot...)" with the proper type - assert_inherits: property "getComposedRanges" not found in prototype chain
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - IdlInterface.prototype.test_interface_of/<@http://web-platform.test:8000/resources/idlharness.js:2917:40
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - Test.prototype.step@http://web-platform.test:8000/resources/testharness.js:2622:25
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - test@http://web-platform.test:8000/resources/testharness.js:633:30
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - self.subsetTestByKey@http://web-platform.test:8000/resources/idlharness.js:44:14
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - IdlInterface.prototype.test_interface_of@http://web-platform.test:8000/resources/idlharness.js:2911:28
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - IdlInterface.prototype.test_object@http://web-platform.test:8000/resources/idlharness.js:2788:31
[task 2024-03-26T14:22:27.375Z] 14:22:27     INFO - IdlArray.prototype.test/<@http://web-platform.test:8000/resources/idlharness.js:760:36
[task 2024-03-26T14:22:27.376Z] 14:22:27     INFO - IdlArray.prototype.test@http://web-platform.test:8000/resources/idlharness.js:755:21
[task 2024-03-26T14:22:27.376Z] 14:22:27     INFO - idl_test/</<@http://web-platform.test:8000/resources/idlharness.js:3529:31
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - 
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - TEST-UNEXPECTED-FAIL | /selection/idlharness.window.html | Selection interface: calling getComposedRanges(ShadowRoot...) on getSelection() with too few arguments must throw TypeError - assert_inherits: property "getComposedRanges" not found in prototype chain
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - IdlInterface.prototype.test_interface_of/<@http://web-platform.test:8000/resources/idlharness.js:2976:40
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - Test.prototype.step@http://web-platform.test:8000/resources/testharness.js:2622:25
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - IdlInterface.prototype.test_interface_of@http://web-platform.test:8000/resources/idlharness.js:2969:20
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - IdlInterface.prototype.test_object@http://web-platform.test:8000/resources/idlharness.js:2788:31
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - IdlArray.prototype.test/<@http://web-platform.test:8000/resources/idlharness.js:760:36
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - IdlArray.prototype.test@http://web-platform.test:8000/resources/idlharness.js:755:21
[task 2024-03-26T14:22:27.377Z] 14:22:27     INFO - idl_test/</<@http://web-platform.test:8000/resources/idlharness.js:3529:31
[task 2024-03-26T14:22:27.388Z] 14:22:27     INFO - ...............................
[task 2024-03-26T14:22:27.388Z] 14:22:27     INFO - TEST-OK | /selection/idlharness.window.html | took 215ms
[task 2024-03-26T14:22:27.389Z] 14:22:27     INFO - PID 2694 | 1711462947354	Marionette	INFO	Stopped listening on port 57065
[task 2024-03-26T14:22:27.903Z] 14:22:27     INFO - Browser exited with return code 0
[task 2024-03-26T14:22:27.904Z] 14:22:27     INFO - Closing logging queue
[task 2024-03-26T14:22:27.904Z] 14:22:27     INFO - queue closed
[task 2024-03-26T14:22:27.929Z] 14:22:27     INFO - Application command: /opt/worker/tasks/task_171146126998253/build/application/Firefox.app/Contents/MacOS/firefox --marionette about:blank -foreground -profile /var/folders/dv/61b_gx3s4ls22w4sk36zffbm000014/T/tmpx6drar_t
[task 2024-03-26T14:22:27.936Z] 14:22:27     INFO - PID 2701 | 1711462929580	Marionette	INFO	Marionette enabled
[task 2024-03-26T14:22:27.937Z] 14:22:27     INFO - PID 2701 | 1711462929781	Marionette	INFO	Listening on port 57077
[task 2024-03-26T14:22:27.937Z] 14:22:27     INFO - PID 2701 | [ERROR error_support::handling] suggest-unexpected: Error from Remote Settings: Error parsing URL: relative URL with a cannot-be-a-base base
[task 2024-03-26T14:22:27.938Z] 14:22:27     INFO - PID 2701 | console.error: URLBar - QuickSuggest.SuggestBackendRust: "Ingest error: Error from Remote Settings: Error parsing URL: relative URL with a cannot-be-a-base base"
[task 2024-03-26T14:22:27.938Z] 14:22:27     INFO - Starting runner
[task 2024-03-26T14:22:28.253Z] 14:22:28     INFO - PID 2701 | 2024-03-26 14:22:28.252 firefox[2701:76307] Persistent UI failed to open file file:///Users/cltbld/Library/Saved%20Application%20State/org.mozilla.firefox.savedState/window_1.data: No such file or directory (2)
[task 2024-03-26T14:22:28.447Z] 14:22:28     INFO - TEST-START | /selection/isCollapsed.html

Hi Sean! Can you also take a look at this please?
Thank you!

Looking, I just made some patches locally, using https://treeherder.mozilla.org/jobs?repo=try&revision=e363a466d7628daf7d8cb6ea4af4334b3770cb05 to verify

Set release status flags based on info from the regressing bug 1867058

I added a patch to Bug 1887881, which should also fix this bug.

The patch from Bug 1887881 fixes this: https://treeherder.mozilla.org/jobs?repo=try&group_state=expanded&resultStatus=success%2Ctestfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=fc04bea78e4515c83accee0470fe4ddbd0997985&searchStr=wpt&selectedTaskRun=OnG5KjnfTmSZbiHpW2YmmA.0