The hpcpush lists in `polygons.cpp` were generated using the game's built-in
polygon editor, which saves its shapes in the form of source code, so they are
indeed the preferred form of modification.

The debian/hyperrogue.png file is a screenshot which can't be easily
reproduced, as it was taken from a random point in the game using the hidden
demo mode (press v, F9) and screenshot (press v, then F8) commands. It was
provided by the author as the source for the icon (.ico) file, and is now used
to generate better icons. It has seen some modification (downscaling and
transparency), but the exact modification steps are lost, so it's now the
preferred form of modification.
