Used as the author of comments and replies you add.
Text recognition, translation, the writing assist and transcription download a model the first time they are used. Your files are never sent.
Most sessions never need this. Two people whose networks cannot be connected directly need a relay (TURN) server to pass the document through, and this app runs none: you can point it at your own. It is stored in this browser, in plain text, like the rest of these settings.