Understand how `hasProxyPrefix` get detected

I’m trying to figure out why so many users have problems running Collabora CODE app within Nextcloud Snap.

While trying to find difference between my own (working) instance and a test-instance, I found out that the one hasProxyPrefix value in capabilities is different. Mine is true. However, I tried to set all app and systen configs of the test system mostly equivalent to my prod.

Now I try to find out what this value basically does and how it is checked. Anyone an idea?

grafik