Less jarring than the keywords blog post to be honest. This doesn't skew away from existing Rust syntax at all, whereas the keywords proposal introduce more syntactic noise.
Well it introduces `yield` and multiple macros. Presumably these would turn into keywords/ syntax at some point.
Pedantically, `yield` is already a keyword [1]. As the project's README states, generators [2] are an unstable part of Rust, and the `yield` keyword goes with them.