We think it's best to never use Flatpak.
Specifically, try not to use Flatpak to install mpv and anki.
Install packages from the official repositories of your distro or from the AUR.
Read the following notes if you still decide to use Flatpak.
Make these changes in Flatseal:
- Enable "Filesystem > All system files"
so it could see
wl-copy. Unfortunately, there's no option to provide only a specific system file. - Add
~/.var/app/net.ankiweb.Ankito "Filesystem > Other Files" so mpvacious could add encoded snapshots and audio to Anki. - Add
PATH=/home/USERNAME/.local/bin:/home/USERNAME/bin:/app/bin:/usr/bin:/run/host/usr/binto "Environment > Variables". There's no option to add a path toPATHin Flatseal, so I opened container, saved it's PATH and added/run/host/usr/binso mpvacuous could accesswl-copy. - Enable "Shared > Network". It's enabled by default, but anyway.
The mpv config root is ~/.var/app/io.mpv.Mpv/config/mpv
~/.var/app/io.mpv.Mpv/config/mpv/scripts~/.var/app/io.mpv.Mpv/config/mpv/script-opts