To all,
although this is an interesting find, I want to warn everybody!
Using those undocumented (hidden) features and assuming they will be always available, is exactly one of those programming habits, which destroys the upward compatiblity of your programs.
Even if it's unlikely this particular thing will change soon, it may change at any time and without warning, latest if some new people get involved in the QB64 development, who have no idea that somebody was depending exactly on that specific behavior, which they just bugfixed, overhauled or whatever change.
And if this happens in 3, 5 or 10 years, I bet you search your ass off to find out, why your program (which was working perfect all the years) does suddenly spit "Invalid handle" messages or at least showing not the expected content anymore.
I'd strongly recommend to everybody:
If you want that QB64 icon in your program, then provide it along and use the documented $EXEICON/_LOADIMAGE/_ICON ways to work with it. There are also several tools in this forum to embed those images.
Best regards