So @Florian Diebold -- I am looking at revising the interface between chalk and its surrounding crate, with a focus on removing "open-ended" callbacks.
PS, I'm not sure if this Zulip stream makes sense or not. =)
Maybe it should just be #wg-traits
(side note, I wish Zulip had a "archive stream" option)
(It seems the official advice is to rename the stream)