Maintain general location” means that Private Relay will choose Relay IP addresses that map to a roughly city-level area consistent with where the user is a...

https://www.apple.com/jp/privacy/docs/iCloud_Private_Relay_Overview_Dec2021.PDF

on a map. For example, Apple Maps shows your current location using a blue marker. Because the precision with which your location can be determined is limit...

https://www.apple.com/jp/privacy/docs/Location_Services_White_Paper_Nov_2019.pdf