FOSS Apps Live in FOSS App Stores!
Don't lock a FOSS Android app in Google's proprietary store!
Many of us are looking to FOSS solutions in order to keep our digital lives under our own control. We don't accept that any Big Tech company should hold the keys to a vast swathe of our digital life. So on our smart phones we may choose to use a FOSS version of Android. That means one that uses the open source parts of Android but avoids the proprietary Google lock-in parts. These so-called “deGoogled” Android-compatible operating systems include LineageOS, Murena /e/-OS, CalyxOS, GrapheneOS and more. Users of non-Google phones can find various “back door” ways to obtain apps from Google's play-by-our-rules-store, but that's completely the wrong way. FOSS apps should be available through FOSS app stores such as F-Droid.
F-Droid is not only an app store, it's also a protocol or “app store kit” that allows anyone to publish their own F-Droid-compatible app store. (I set up one up just to publish one camera app for myself and friends.) Each app publisher can choose whether to publish their app in the F-Droid store following its rules and conditions, or publish on their own store where they can set their own rules and conditions. Each user can decide which F-Droid-compatible stores they want to use, according to their own assessment of the publisher's reputation.
These fine FOSS people do it right
- FUTO Circles a.k.a. Circuli, matrix-based private social media — published in their own f-droid repo 
These fine FOSS people need a nudge
TODO: add lots more examples
 An f-droid repo link is not a web page. To use it, you open your f-droid app's “repositories” settings and add the link there.