It does! The API framework as a whole is at https://github.com/wikimedia/restbase and you want
https://github.com/wikimedia/restbase/blob/master/specs/analytics/v1/pagevie... and https://github.com/wikimedia/restbase/blob/master/mods/pageviews.js for the pageviews-specific modules.
And Chris, you're welcome to #wikimedia-analytics to ask any questions you might have. I'm known as milimetric around those parts :)