Nit rebuttal: I was referring to the F-Droid repository which I thought was clear from context. These elements are scanned for and apps called out (tagged) should they contain something not-free, even connecting to network services like Reddit or Twitter. The are referred to as Anti-Features: https://f-droid.org/en/docs/Anti-Features/

Sorry! I understood you to be saying that the definition of FOSS includes no ads or trackers, and I wanted to make sure no one was misled by that.

Additionally, as you say, the F-droid repository does contain apps with those properties; they're labeled, not excluded.

Trivia: by default (unless it has changed upstream), the F-Droid app defaults to "Include anti-feature apps: Off" in the Settings. The user must go in there and manually opt-in to see all the anti-feature apps on the mobile client.

It doesn't actually hide apps with "anti-features", you can still see them by default. The only thing it does is hide the description and install button of apps with "anti-features" in the search screen. It seems like a half-baked feature.