There was a question posted on the announcement for 3.6 by capeman29:
Capeman29 • 2 days ago
What is this “Libretro-MAME (based on the most recent version of MAME)” – I’m not seeing it on the mame documentation page. Is it an update to lr-mame-2010 or is it a whole new core based literally on mame 0.171? That would be awesome if it was!
I’m curious as well as I haven’t been able to find any info regarding a new libretro mame release, or I’m just blind!