On the client download page, you can download any compiled version, including the experimental/testing ones. However, the only mention of where to view the source is on Github, but there have been no Github commits at all since 2 Oct 2017. There have been three experimental/testing "releases" since the last stable release (2.13.6 on 19 Sep 2017), so obviously the code is changing.... just not on Github. The PPA repository doesn't seem to provide the source, either (tested with "deb-src" + same URL in the sources.list file).
If Eddie is going to be open source, can the source please be.... open?