dirname() is a slow function compared with __DIR__ and using
'/../'. Moodle has a large number of legacy files that are included
each time a page loads and is not able to use an autoloader as it is
functional code. This allows those required includes to perform as
best as possible in this situation.
A generic OAuth 2.0 for the web application flow, tested against
microsoft and google apis.
Added a callback endpoint for requests so that clients can use a single
endpoint (without GET params). I put this in /admin/ as I expect some
sites will have .htaccess denying access to /lib/.
Jake Dallimore