I went looking in the forum for any interest in IndieWeb because that is a community I am interested in, and found a reference to Webmentions in the discussion about removing Pingbacks.
As I am sure some people know, there is a full suite of WP plugins that enable various aspects of the IndieWeb protocols. I do not in fact make much use of them in my own ClassicPress site, although the bits I do use, such as Webmentions from Twitter, continue to work well.
I am not a developer and so could not help directly, but I invite anyone who might be interested in forking these plugins to drop by the IndieWeb discussion β which is also available via IRC, Matrix and Slack β to see whether there could be good opportunities.