How to change Blender UI icons?

I would like to change a few Blender icons from the UI. Sadly, I found that the icons are in some strange .dat file format in blenderversion/datafiles/icons. Is there, perhaps, a way to change the icons? Preferably without re-compiling the entire thing? Thanks!

Yep:

I want to change an existing icon, like the Particle Properties icon or the Render Output icon.

Oh yeah you’re going to have recompile for that

Oh man! Well that stinks!