I didn't exactly follow the test plan but I can confirm that WebExtensions work in the firefox-native-messaging.
I already had the xdg-desktop-portal from proposed and had Firefox snap from latest/beta channel and that didn't work. I installed that testing snap manually with the --dangerous flag
and when I opened it under GNOME Shell there was the modal dialog. I clicked allow and then opened the local extensions page and I can see all the extensions. Also I can enable or disable them and also change their settings.
I didn't exactly follow the test plan but I can confirm that WebExtensions work in the firefox- native- messaging.
I already had the xdg-desktop-portal from proposed and had Firefox snap from latest/beta channel and that didn't work. I installed that testing snap manually with the --dangerous flag
snap install firefox_ 103.0b9- 1_amd64. snap --dangerous
and when I opened it under GNOME Shell there was the modal dialog. I clicked allow and then opened the local extensions page and I can see all the extensions. Also I can enable or disable them and also change their settings.