This is a Nextcloud app which can be used to track the location of a user or device. It is based on the OwnTracks which provides apps for Android and iOS.
In order to store your location on your Nextcloud you need a OwnTracks app, set
the mode to HTTP Private, add the url https://<yourNextcloud>/index.php/apps/locationtracker/api/v1/location
and enable authentication with your Nextcloud user name and password.