There is an updated pull request by oreo639 against master on the void-packages repository

https://github.com/oreo639/void-packages gdmenv
https://github.com/void-linux/void-packages/pull/39265

flatpak: fix setting environment variables on gdm
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#### Testing the changes
- I tested the changes in this PR: **YES**

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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A patch file from https://github.com/void-linux/void-packages/pull/39265.patch is attached