And does it work in the background even after you kill the foreground app?
Share Your Location Live PRIVATELY
https://github.com/Myzel394/locus
Locus is a free, open source app for Android and iOS that allows you to share your location live. It encrypts your location end-to-end, meaning that no one, not even we, can read it. It stores the location decentralized on multiple servers of your choice using Nostr, meaning that you are not locked to a service. No authentication required.
Discussion
Good question, I do not know. However, the author has a Mastodon presence and an e-mail address: https://github.com/Myzel394