Kept on the Kindle, locked with its PIN (any computer can sync it with the PIN). Grimmory's password isn't kept: it stays signed in with a sign-in token.
Grimmory
Not connected
Notes (Memos)
Not connected
Calendars
None yet
Add a calendar
Many calendar servers (Google, Proton…) don't let web pages read their links. Then download the calendar as an .ics file and add the file: each sync on this computer reads it again.
Immich (Photos)
Not connected
Pictures from one of your albums for the sleep screen and the Home wallpaper, made here to fit the Kindle's screen. Immich only answers web pages it's told to: what to add to your server.
For the sleep screen: Content → Sleep screen pictures. Each sync brings new pictures from the album.
Music (Plex)
Not connected
FLAC and other formats the Kindle can't play are converted to MP3 by your Plex server at this quality. As on the Kindle (Music tab → Plex), where the choice is kept.