Why do you assume that someone wishing to build from source sets out to "contribute"?
Well it is linked on the download page but discretely in the bottom right-hand corner, which is easily missed because we find "Development versions" section higher up. That link takes us to a page where weekly builds AND recent master source code is provided but with NO link to build instructions.It is not via download because download addresses users/testers.
That is why I was unable to find it initially and that was quite frustrating.
"Development versions" links to a page with various download links introduced by this text:
That is missing a fourth entry:Various bundles are offered here, which are renewed weekly.
1 Appimages (conda-based) run on most Linux distributions.
2 Dmg's (conda-based) run on osx.
3 There are different versions for windows
4 Recent source code archive. Build instructions can be found here .... https://wiki.freecad.org/Compiling
Maybe it would be helpful to add something like that so that you don't need to discover one path, get the source code, then forget why you went there and discover a separate path to the build instructions.
Downloads | Development versions would seem a direct and logical path to follow when looking for source code, and it provides it. It would be helpful if it provided a link to how to make use of it.