Chrome Stable (m96) exposes the following properties on the i18n API
Chrome Canary (m98) exposes the following properties on the i18n API
The commit you linked explicitly says it adds getUILanguage and detectLanguage (which it did). The getMessage method is still a work in progress. The problem with that method is that it is a synchronous API (SWs are async) and the implementation needs to be moved to a different process in the browser.
What portions of your UI cannot be localized in Manifest V3? You mentioned context menus; are there any other areas of concern?
Simeon - @dotproto
Chrome Extensions DevRel