That's correct. Sorbet currently uses RBI but after meeting with core they standardized on RBS and are migrating to present a more unified front and enable easier development of type checking libraries on top of it.
Very little of this will need to be written by hand. The underlying tech is pretty decent at guessing types, the idea is that if it's not quite specific enough you adjust it, but it should otherwise be transparent.
Very little of this will need to be written by hand. The underlying tech is pretty decent at guessing types, the idea is that if it's not quite specific enough you adjust it, but it should otherwise be transparent.