"F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device."
It serves as an app store for Google-free Android devices like CalyxOS, Replicant, CopperheadOS, GrapheneOS, Lineage-for-MicroG, Fairphone Open, and more. It puts a strong emphasis on privacy, with no user accounts at all, and active work to remove metadata leaks.
Take a look at this Weblate Starter Tutorial to learn how to sign up and use Weblate.