You can clone with
HTTPS or Subversion.
Trying to start it on the 9/26 Thunderbird Daily gives the error:
Error: TypeError: server is undefined
Source file: chrome://mozlab/content/mozrepl/overlay_impl.js Line: 60
Actually, I installed MozLab because it was all I found on Thunderbird side. I now see its an older version of MozRepl. But I also see that you removed Thunderbird from the install.rdf in 2009 in SHA: ed23630. So I guess Thunderbird is no longer supported?