Thank you (and others) for providing such an amazing suit of software.
It might be overkill to change the INDIWebManager template .service file, particularly if it's specific to Raspbian and if the GSC instructions make it clear.
I was previously on UbuntuMate but for a rebuild became worried about the slow/delayed update release timescales for RPi versions and as the underlying OS is pretty much the sam and as it's a tool (small black box) Raspbian would undoubtedly "do the job".
I'm probably unusual in wanting totally headless, but I'm very aware of how limited RPi RAM is (and I'm open to suggestions from others).
Well we should probably at least mention it in the documentation. I know I couldn't figure out why it wasn't getting the environment variable and I finally just gave up and changed my script to compensate. So we should get the info out there someplace.