(2023-12-06, 17:13)Travis Cobbs Wrote: This is not part of LDraw, but instead a separate snapping database that LDCad maintains. It's worth mentioning that since this database is manually created and maintained, it won't necessarily be exhaustive. In any event, Roland Melkert, the author of LDCad, can hopefully help you. (I know about the existence of LDCad's snapping database, but don't know anything about its details.)
I released the LDCad snapping information on GitHub awhile ago, it's free to use as long you share any derived data for free too (CC-BY-SA-4.0 license).
https://github.com/RolandMelkert/LDCadShadowLibrary
documentation (slightly out dated)
https://www.melkert.net/LDCad/tech/meta
A (compressed) version of it is included in the latest LDCad too.
But please note this information was always only intended as a placement helper during editing, it isn't suited for full-blown physics etc.