Description of problem: The URL specified in the package description leads to a HTTP 404, not found address https://src.fedoraproject.org/rpms/muParser/blob/rawhide/f/muParser.spec#_13 points to https://beltoforion.de/article.php?a=muparser , which doesn't exist
Correct URL might be https://beltoforion.de/en/muparser/ now, but not sure. Might be worth asking upstream?
This bug appears to have been reported against 'rawhide' during the Fedora Linux 38 development cycle. Changing version to 38.