There are two new translatable strings in mutter, merged as part of settings: Add output luminance settings to org.gnome.mutter (!4271) · Merge requests · GNOME / mutter · GitLab. The strings are part of the settings schema, and are these two in particular: settings: Add output luminance settings to org.gnome.mutter (!4271) · Merge requests · GNOME / mutter · GitLab
For reference, here is the freeze exception: String freeze exception request, mutter (#254) · Issues · Teams / Translation / Coordination · GitLab