As I look into remounting the filesystem, I get permission errors on attempting to open the directory.
Keybase is a bind mount to the original keybase filesystem. I cannot export to that filesystem, or access it from within Joplin, even though it is a bind mount.
The logs give:
Sep 24 17:05:52 ThinkPad-X1-Carbon-7th audit[4492]: AVC apparmor="DENIED" operation="open" profile="snap.joplin-james-carroll.joplin" name="~/Keybase/" pid=4492 comm="pool" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
However, when trying to sync to such a directory, I get no errors in the logs.
Now when I try to sync to the directory, Joplin gives appropriate errors in the bottom left corner. However before, it was silent.
I'm quite finished fiddling with this. If I have any problems with the AppImage, I will open a new issue.