Locally, I run a Pi-Hole to provide ad blocking on the local network¹ but I also run a Docker server to which I want to forward various subdomains (which are then routed to containers using Træfik). I had this set up, but my upgrade from v5 to v6 of Pi-Hole blew this away (as I needed a new SD card for the Raspberry Pi it was running on) (see also the v6 release notes).