weblib.py provides a way to obtain Wayback Machine and WebCite archive urls for Internet resources. It uses a custom and simple API for each service. These weblib methods are only used by scripts/weblinkchecker.py , which prefers Wayback over WebCite.
Wayback has had support for the Momento protocol for many years now. Using Momento for accessing archived versions of Internet resources allow multiple implementations using the same protocol, and the Internet resource can also provide their own Momento support (and MediaWiki has an extension which supports this).
Our WebCite code also uses a custom API. I could not find a Momento API for WebCite.
weblib.py should provide plumbling for obtaining an archived version of a internet resource, and attempt to use the original resource or Momento providers like Wayback, and any non-Momento providers (WebCite?). It should have a default algorithm for picking the 'best' archived version, but allow callers to override this with a specific preference.