I am having a problem with Rift not being compatible with certain datapacks like the magic-sorting-system datapack. Minecraft will load but as soon as I try to open a world my game crashes...!?!?!?!???

Known issue, already fixed in dev.

What is "dev"?

Development.........most devs abbreviate it because everyone refers to it as dev and no real reason to say the full term. Its basic mod lingo