According to documentation, browser_style support gets removed with FF118 (planned release date: 2023-09-26), breaking the current design of the sidebar and options page.
Previous revisions of the documentation are wrong, Firefox is only removing the support for browser_style in MV3, not in MV2, which would also be an unnecessary breakage.
https://bugzilla.mozilla.org/show_bug.cgi?id=1827910
According to documentation,browser_stylesupport gets removed with FF118 (planned release date: 2023-09-26), breaking the current design of the sidebar and options page.Previous revisions of the documentation are wrong, Firefox is only removing the support for
browser_stylein MV3, not in MV2, which would also be an unnecessary breakage.https://github.com/mdn/content/pull/26642/files#diff-cee78116d97bed12a460748c8aa5ca263663db047cde0923caa01dc1da8c307cR87
https://bugzilla.mozilla.org/show_bug.cgi?id=1830712
https://searchfox.org/mozilla-central/rev/ad732108b073742d7324f998c085f459674a6846/browser/components/extensions/extension.css#28-552
https://hg.mozilla.org/mozilla-central/raw-file/a445f1762c895000bcdabd9d95697522359d41ed/browser/components/extensions/extension.css
Anyway, long-term it is necessary to migrate anyway.
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/user_interface/Browser_styles#manifest_v3_migration
browser_action- 34882509c55e683cd84856ce3c7bb548b945caf6options_ui- 5bf368dcfc0bde9c027274de8d7e6b2006e95fb0sidebar_action- 030f534b92e93e7c755dcd1bf07e2336fd47f7c5