You have to search for the pull requests on github
https://github.com/pi-hole/pi-hole/pulls?q=is%3Apr+remove+list+is%3Aclosed
E.g.
https://github.com/pi-hole/pi-hole/pull/3937
https://github.com/pi-hole/pi-hole/pull/3451
https://github.com/pi-hole/pi-hole/pull/3287
https://github.com/pi-hole/pi-hole/pull/3236