There's a merged pull request on the void-packages repository

flatpak: fix setting environment variables on gdm
https://github.com/void-linux/void-packages/pull/39265

Description:
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#### Testing the changes
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This doesn't affect `GDM -> gnome` due to: https://github.com/void-linux/void-packages/pull/9126
However it does affect `GDM -> <anything other than gnome>`

See: https://wiki.gnome.org/Initiatives/Wayland/SessionStart

(`/etc/profile` never gets loaded in GDM)

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