what is /run/user/1000/doc?

[zBeeble]

So... I understand what /run, /run/user and /run/user/1000 are.

(B)(root@steamdeck deck)# ll /run/user/1000
ls: cannot access '/run/user/1000/doc': Permission denied
total 4
-rw------- 1 deck deck  54 Aug 22 00:03 0fbc4d33-e861-4f87-b63c-b694bcd3128f
drwx------ 3 deck deck  60 Aug 22 00:03 app
srw-rw-rw- 1 deck deck   0 Aug 22 00:03 bus
drwx------ 3 deck deck  60 Aug 22 00:03 dbus-1
drwx------ 2 deck deck  60 Aug 22 00:03 dconf
d????????? ? ?    ?      ?            ? doc
srwxr-xr-x 1 deck deck   0 Aug 22 00:04 gamescope-0
-rw-r----- 1 deck deck   0 Aug 22 00:04 gamescope-0.lock
drwx------ 2 deck deck  80 Aug 22 00:04 gamescope.rbxbO7y
lrwxrwxrwx 1 deck deck  32 Aug 22 00:04 gamescope-stats -> /run/user/1000/gamescope.rbxbO7y
-rw-r--r-- 1 deck deck   0 Aug 22 00:04 gamescope-stats.lck
drwx------ 2 deck deck 140 Aug 22 00:03 gnupg
srwxr-xr-x 1 deck deck   0 Aug 22 00:04 kwallet5.socket
drwxr-xr-x 2 deck deck  60 Aug 22 00:03 p11-kit
srw-rw-rw- 1 deck deck   0 Aug 22 00:03 pipewire-0
-rw-r----- 1 deck deck   0 Aug 22 00:04 pipewire-0.lock
drwx------ 2 deck deck  80 Aug 22 00:04 pulse
drwxr-xr-x 6 deck deck 160 Aug 22 00:03 systemd
(1)(B)(root@steamdeck deck)# ll /run/user/1000/doc
ls: cannot access '/run/user/1000/doc': Permission denied
(2)(B)(root@steamdeck deck)#

... can't chmod it. Can't rm it. What is it?

[PopinFRESH]

Its a fuse for the document (e.g. doc) portal to implement per-application sandboxing.

https://bugzilla.redhat.com/show_bug.cgi?id=1913358
https://bugs.launchpad.net/ubuntu/+source/xdg-desktop-portal/+bug/1905623

etc.

EDIT: for clarity, it is being used by flatpak. You can't chmod or rm it because it is immutable and also not owned by the user trying to execute those commands (e.g. deck or root).