Initially it was based on libwebsockets 3.1, but then I made it compile for Debian 10 in order to use it for rtpengine websocket control. I forgot to update the docs -- did it in master a few minutes ago, will backport.
Anyhow, in short, it compiles fine on Debian 10 and iirc Richard tested the module when adding websocket support to rtpengine module.