LICENSE file is only included in base package, i.e. cups.
According to Fedora Licensing Guidelines
the -libs subpackage must also include a copy of license text.
Q. My package generates a foo and foo-libs package. foo has the license
files, and foo depends on foo-libs, but foo-libs doesn't have any
license files in it. What should I do?
A. You have two options here. You can either move the license texts from
foo to foo-libs or duplicate the license texts in both packages. Moving
the license texts is an acceptable option in this case because it
ensures that if foo-libs is installed, the license texts are present,
and if foo is installed, it will pull in foo-libs, thus, the license
texts are present.