A little tangential, and maybe it goes without saying,
but I really like that MediaWiki API points to documentation in-band when fetched via browser (without the format option). For example:https://en.wikipedia.org/w/api.php?action=query&prop=pageimages&piprop=thumbnail&pithumbsize=96&pilimit=50&generator=prefixsearch&gpssearch=tomato&gpslimit=50Although a nice improvement would be to link to the specific API used.