In a similar fashion to Okular commit df5364d (and probably others
spread across KDE's repositories), we need to install a hicolor
version of our icons so things such as menu entries are shown with an
actual icon in non-KDE desktops.

... And it is time for some history digging once again.

Until the 3.5 series, Ark had its set of icons which were correctly
installed according to the icon naming spec. During the transition
from the Crystal to the Oxygen icon set, for some reason it was
decided that some applications should start using more generic names
for their icons. Some of those names are defined in the icon naming
freedesktop.org spec, so other desktops are expected to have their own
versions available anyway. KCalc uses accessories-calculator, for
example.

According to [1], however, some icons fell in the category of

  "not in the spec, but let's keep it out of there anyways,
   it's not really suited to be a standard icon".

This happened to "utilities-fi...