Wow, after so many useless bloated Electron based applications over the years, this is like a breath of fresh air. This is so fast, lightweight, portable, and uses only 17 MB of memory with XL icons of over 10k photos. Very impressive. If only more developers would quit their laziness and make such software again.
Totally agree! Let's make a real joy such like this one. I feel a great sense of satisfaction and excitement watching the File Pilot development process.
It looks like WPF but isn't. Sibling comment suggests sui generis, which explains the tiny size and lack of dependencies. This does make it blindingly fast but makes the keymappings different from what you'd normally expect. Haven't tested annoying cases e.g. two monitors with different DPI.