chardetng has been on crates.io for a while, but now it has undergone a couple of rounds of improvements to reach the point where it makes sense to write about it and to announce it.
It's a character encoding detector to be used when consuming encoding-unlabeled legacy Web content. If your app needs to consume the long tail of legacy Web content, this crate is probably of interest to you. If you don't need it, you should be happy about not needing it.