One of the core bits of infrastructure I use as a maintainer is Patchwork (I wrote about making it faster recently). Patchwork tracks patches sent to a mailing list, allowing me as a maintainer to track the state of them (New|Under Review|Changes Requested|Accepted etc), combine them into patch bundles, look at specific series, test results etc.

https://www.flamingspork.com/blog/2018/08/22/pwnm-sync-synchronizing-patchwork-and-notmuch/