I think they are referring to crates vs binaries vs cargo binaries.

Crates are your libraries, not meant to be standalone, binaries are your .exe, cargo binaries are meant to be compiled by cargo on your machine and run through cargo, ex: cargo sqlx

They might also refer test binaries and example binaries which are two executables that only compile the tesrs and the examples to make sure they work, but apart from that idk

And there’s also WARs for servelets, uberjars, various means of bundling for exes, native compilation via Graal. Overall quite the ignorant meme.