See also data sent to supl.google.com (Android default).

> SUPL is used as part of the A-GPS (Assisted GPS) system to get a faster Time to First Fix. The problem is that Android's implementation automatically sends the IMSI (ID of the SIM card) to the SUPL provider for no apparent reason. And because Google is the default provider it's a big breach of privacy. [1]

[1] https://github.com/Magisk-Modules-Alt-Repo/supl-replacer

You can mitigate it by cutting it down to three months of history. I also enabled enough privacy settings that they report long outdated home and work locations on the map.