This is coming from Bug 1411358 where we can see that the most frequent tasks that are hitting the max run time are these mochitests with networking on socket process and only on linux debug: https://treeherder.mozilla.org/intermittent-failures/bugdetails?startday=2023-03-02&endday=2023-04-01&tree=trunk&failurehash=all&bug=1411358

The run time for these falls now under .*/debug: 5400 - https://searchfox.org/mozilla-central/source/taskcluster/ci/test/mochitest.yml#279
I don't see any obvious hangs in the logs, looks like the tests need more time to go through the whole manifests.

Some logs examples would be:
https://treeherder.mozilla.org/logviewer?job_id=410926234&repo=autoland
https://treeherder.mozilla.org/logviewer?job_id=410731504&repo=autoland
https://treeherder.mozilla.org/logviewer?job_id=410926235&repo=autoland
https://treeherder.mozilla.org/logviewer?job_id=410707595&repo=autoland

The manifests in the jobs timing out are:

    browser/base/content/test/statuspanel/browser.ini
    browser/base/content/test/tabPrompts/browser.ini
    browser/base/content/test/tabdialogs/browser.ini
    browser/components/enterprisepolicies/tests/browser/disable_fxscreenshots/browser.ini
    browser/components/newtab/test/browser/browser.ini
    browser/components/urlbar/tests/engagementTelemetry/browser/browser.ini
    browser/extensions/formautofill/test/browser/focus-leak/browser.ini
    dom/security/test/sec-fetch/browser.ini
    dom/workers/test/browser.ini
    toolkit/components/aboutthirdparty/tests/browser/browser.ini
    toolkit/components/antitracking/test/browser/browser.ini
    toolkit/components/extensions/test/browser/browser.ini
    toolkit/components/messaging-system/schemas/SpecialMessageActionSchemas/test/browser/browser.ini
    toolkit/components/places/tests/browser/browser.ini
    toolkit/components/resistfingerprinting/tests/browser/browser.ini
    toolkit/components/telemetry/tests/browser/browser.ini
    toolkit/components/viewsource/test/browser/browser.ini

https://hg.mozilla.org/mozilla-central/rev/54a22f5e87f7