On Meta there's a list of mailing lists that mentions "wikimedia-search",
but that list seems to be dead and the archive is full of spam.
Another list exists, called "discovery", but not listed on Meta.
https://lists.wikimedia.org/hyperkitty/list/discovery@lists.wikimedia.org/

Indeed the Discovery list is the one I've seen get Search-related traffic.  I wanted to update the relevant Meta page but got very lost when I saw the translate tag inside a row table template with an identifier (397).  The list that's listed under Search and Discovery hasn't seen actual traffic from anyone on the search team in over 7 years.  The discovery list I linked here is the appropriate substitute, if anyone knows how to edit that scary template thing.