Just learned that the Translations feature on Firefox desktop can be used by itself! A test page is shipped and is accessible at about:translations that allows users to enter the text to translate and the languages to translate from and to.

When Firefox shipped Translations originally, I've always wanted to be able to use it stand-alone especially as an alternative to Google Translate. On Android, there is an offline translate tool that someone has built which uses the models from Firefox.

Source for the about:translations