Funny, I maintain xfdesktop (the Xfce component that draws the desktop background and icons), and this past summer I just did a major refactor/rewrite of how xfdesktop saves and restores icon positions as well.

Fortunately I didn't have as much trouble in the "reading code is the hardest part" dimension, as I was largely redoing code I myself wrote around 20 years ago (though others had changed it a bit in the meantime).

It's fun to see a lot of the same problems I had when modeling how all of this should work. Xfce 4.20 (probably end of next month) will have all of my changes for this, but of course I expect I've broken some things as well and will have to add in a bunch of little hacks and workarounds. It's a truly weird, complex problem, even though at first look it feels like it should be simple.