The homepage tag redirects to issues instead. Both should be in use.

Note that the issues field (like all other metadata fields) is completely optional according to the fabric.mod.json spec.

I suppose this issue is because by default ModMenu displays the issues field in its button instead of the sources one (which is actually more common), right?

I suppose this issue is because by default ModMenu displays the issues field in its button instead of the sources one

Yes. Just wanted to make any use of these buttons since they are there.