Consider adding support for Wallpaper portal
https://flatpak.github.io/xdg-desktop-portal/#gdbus-org.freedesktop.portal.Wallpaper
This should make it possible to set wallpaper without poking holes in the sandbox:
Edited by bbhtt
https://flatpak.github.io/xdg-desktop-portal/#gdbus-org.freedesktop.portal.Wallpaper
This should make it possible to set wallpaper without poking holes in the sandbox: