I use /e/OS on a Fairphone 6, and when I open the quick settings screen, the bottom shows two running apps: Advanced Privacy and ntfy.
I understand Advanced Privacy - what is ntfy doing?
A service that brings Unified Push notifications onto your device. Can be used by Molly, Foss Warn and others. The same like the ntfy app from F-Droid.
Thanks. Is it possible to work out which apps are using it? Presumably it was pre-installed as a part of /e/OS?
The original ntfy from F-Droid has a user interface showing all that. The now integrated ntfy has no user interface at all, its just an always running service.
At the moment it should be your messaging apps, if you pay attention to UnifiedPush. But it could also be also used for warnings of flooding, etc. (alerts) if you install a app which supports it. I don’t recall all the cases. It is a open source replacement for FCM (Google service for notifications) which your (if you didn’t deactivate it on purpose) and my degoogle device still uses to get notifications.
The good thing is, it shouldn’t do anything if you don’t need it, this means: if you don’t have an app that uses it. I don’t think you could quantify it’s energy consume in this idle running or so.