Hi,

Downloading your repo from github is a problem for
anonymous users not using the ssh protocol.  When the submodule is downloaded,
git asks for a password.  

Would it be possible for you to use:

url = <https://github.com/xroche/coucal.git>

as the url instead of 

url = git@github.com:xroche/coucal.git

Thanks,

===Rich