Some comments from the Debian side (please share them accordingly).

pegasus-source-4.8.0.tar.gz

• contains a full copy of .git/ (making the tarball 2.5 times the necessary size)
• doesn't contain debian/changelog (but debian/changelog.in), and I cannot find
  a rule to create one
• unpacks to pegasus-source-4.8.0 (I'd expect pegasus-4.8.0)

A "stripped" source tarball can be extracted from pegasus-4.8.0.src.rpm

• that doesn't have .git inside
• that comes with a debian/changelog file (build version is -1+deb9, btw)
• that still unpacks to pegasus-source-4.8.0

So here's what I did:

• fetch .src.rpm
• extract .tar.gz (and ignore .spec)
• rename to pegasus_4.8.0.orig.tar.gz
• unpack, and rename directory to pegasus-4.8.0
• edit debian/changelog so the first entry reads "pegasus (4.8.0-1)"
• process the package similar to the LSCsoft ones (to create a deb8u0 and deb9u0 source package
  to be handled be the respective pbuilders)

First attempt to build fails as docbook still is expected to come from the net -
which is "verboten" for pbuilder. Also, a patch has still to be applied to avoid
overwriting of debian/changelog.