Given following log snippets, their explanation, and nothing else, explain what failure, if any, occurred during build of this package.

  Snippets are in a format of [X] : [Y], where [X] is a log snippet, and [Y] is the explanation.

  Snippets are delimited with '================'.

  Drawing on information from all snippets, provide a concise explanation of the issue and recommend a solution.

  Explanation of the issue, and recommended solution, should take a handful of sentences.

  Snippets:

  [Checking for unpackaged file(s): /usr/lib/rpm/check-files /builddir/build/BUILD/fwupd-2.0.8-build/BUILDROOT
error: Installed (but unpackaged) file(s) found:
   /etc/grub.d/35_fwupd
RPM build errors:
    Installed (but unpackaged) file(s) found:
   /etc/grub.d/35_fwupd]: [RPM complains about unpackaged files.]

Issue: The build failed due to extraneous files being found in the RPM installroot that weren't part of the final RPM(s).
Resolution: Make sure all files that are installed during the %install section are mentioned in the %files section in the specfile.