No as in, this is not the Android backup system, but rather something custom-built by Signal? If so, how do I enable this on my phone, and what's that passphrase the tool alludes to? I don't see an option to set one in the Android app.
Yes it's custom-built by Signal. I thought it was enabled by default — I don't remember ever turning it on — but it might not be. Here is how to do it:
> Your backup folder is listed under Signal Settings profile_avatar.png > Chats > Chat backups > Backup folder. Use the files app or plug your phone into a computer to go to the folder.
> For older versions of Signal, the backup file signal-year-month-date-time.backup can be found at /Internal Storage/Signal/Backups or /sdcard/Signal/Backups
