It seems that most mods can't insert/extract/read the contents of a package with the exception of botania's corpora which can extract from packages but can't insert for some reason (pictured).

Mods need to support vanilla Container, forge used to wrap containers with iitemhandler im pretty sure but i guess they dont anymore because this loader is ass

Thinks about it for 3 more nanoseconds after sleeping a bit

I guess it's not that hard to use the forge capabilities system to implement IItemHandler.. workin on it

Yeah, that wasn't so hard

check for version 3.1, there's no Fabric release with this version because there were no fabric changes (so the version numbers are now out-of-step)