I bought the PRO version for linux recently. From what I understand, the code limit is 65k, however... I can input in my editor 512K worth of code. I saw an earlier post by the developer saying code banks aren't a thing anymore and that the limit is 65K of compressed code for the PRO version. Can someone explain what's going on? 

I don't know anything about the subject, but it sounds like your 512K of code is compressed to less than 65K?

I don't understand the limits either. The code editor in TIC80 still counts each character as a token, and doesn't specify where the limit may be. I have no idea what "64k of compressed data" means in practice.