Download page offers "source" for Tor, but everything else on that page is Tor Browser
Our download page offers Tor Browser for various platforms, and also a "source" option. But the source option only gives you a Tor tarball, and that's not the source for the binaries on that page.
Maybe we should have a web page for the little-t-tor component, with pointers to things including source tarballs.
And then change the download page to give you pointers on how to reconstruct the tor browsers that it offers (which is actually quite hard, but that's another matter).