the sample files i've been issued have GUANO metadata saying they come from here https://www.pippyg.com/pipistrelleprev.html which looks wonderful but is all in a "non-commercial" grey area, no schematics, future development now in these hands https://www.apodemus.eu/nl
of course libbymiller (npub1eg6…a5fm) has experimented with one https://mastodon.me.uk/@libbymiller/114870236050202877
goodness i have a lot to learn quite quickly rn