>The feature is marked as disabled in Firefox 98. And indeed it is: https://searchfox.org/mozilla-central/source/modules/libpref/init/StaticPrefList.yaml#8915 So to answer the question: nothing "landed in a stable release", this configuration was never supported yet because of bugs like this one.
Bug 1751363 Comment 29 Edit History
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>The feature is marked as disabled in Firefox 98. And indeed it is: https://searchfox.org/mozilla-central/source/modules/libpref/init/StaticPrefList.yaml#8915 So to answer the question: nothing "landed in a stable release", this configuration was never supported nor released yet because of bugs like this one.