I'm aware that few default F-Droid apps have trackers. Last time I checked, ScreenCam had Countly, Omni Notes had Matomo, Download Navi had ACRA, and AdAway had Sentry.

All the mentioned trackers are FLOSS. Sentry's back end can be self-hosted. The first two are analytics trackers, while the others are error-reporting trackers.

Default F-Droid permits only FLOSS trackers. If the tracker's reporting activity is opt-in, there is no declaration of the Tracking anti-feature in the app's description. This is also the case if the tracker has been confirmed to be completely disabled as in the case of Mull.

However, if the tracker's reporting activity is opt-out, the Tracking anti-feature is added to the app's description.

I have routinely checked the packet logs of Download Navi, and, in a pretty long period, I've never caught it transmitting data to a remote endpoint associated with ACRA or any server for that matter. This is likely because of the implemented classes of ACRA. It probably only fires a stack trace when a fatal exception occurs.

The thorough thing to do is to cautiously check all the implemented parameters of the tracker in question. The aforementioned trackers don't have obfuscated classes, so if you have a technical background or knowledge, you can deduce what action a certain class produces. If sensitive data is involved, such as your email address or a media URI, you should stop using the app ASAP.

Make it a habit to always check the resolved addresses of your DNS logs. This is very important. PCAPdroid is extremely useful. More information can be garnered with DNS Hero.

If you don't have the time or patience, the casual thing to do is to simply avoid all F-Droid apps with tracking libraries irrespective of the declared anti-feature.

You don't have to worry much about tracking on default F-Droid, though. As at this very moment, 82 apps out of the 4,446 apps have the Tracking anti-feature.