Do you have an example link?

For me:

http://data.guix.gnu.org/repository/1/branch/master/package/mame

and

http://data.guix.gnu.org/revision/1d9b4664e30ce3f79606bf1167a2fca9bf4abba2/package/mame/0.218

only shows "unknown" build status.

-- 
Pierre Neidhardt
https://ambrevar.xyz/