Flatseal offers the possibility to add, remove and edit the environment variables of any flatpak program installed, flatpak-kcm doesn't offer this instead.
STEPS TO REPRODUCE
1. Open flatpak-kcm
2. Select any installed flatpak program
Cannot find the section about the environment variables of that program
Find the section about the environment variables of that program where you can add, remove or delete said variables.
Operating System: Manjaro Linux
KDE Plasma Version: 5.27.4
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8
Kernel Version: 6.2.10-1-MANJARO (64-bit)
Flatpak Version: 1:1.15.4-1
Environment variables support has been fixed and will be added back in 5.27.5
*** This bug has been marked as a duplicate of bug 464876 ***