It makes it easier to document many kinds of functions/methods in
sphinx, including async functions, abstract methods, generators, etc.
I originally wrote it for the trio  project, hence the name, but
don't let that put you off -- there's nothing about it that's specific
to trio, or even to async/await (except that projects that use
async/await *really need* an extension like this). Really I think this
extension ought to be a standard feature of sphinx. But in the mean
time, it's pretty handy.