See also this for contributing to #beaconDB via #geoclue:
https://fosstodon.org/@kop316/113592275375591725
With the help of @beacondb , I was able to fix geoclue not being able to submit new locations to beaconDB! The MR is here: https://gitlab.freedesktop.org/geoclue/geoclue/-/merge_requests/192
With that fixed, I made a Linux mobile stumbler that works with geoclue to submit data! You can find it here: https://gitlab.com/kop316/geoclue-stumbler
(Note that you'll need that patch for the stumbler to actually submit data).