Light Matter is a simple image viewer with HDR and wide gamut photo support for Windows. It also supports modern image formats like JPEG XL and AVIF. HDR is supported in JPEG UltraHDR (JPEG with gain maps), JPEG XL, AVID and PNG.
Version 0.0.5 was released recently and it is now published to Microsoft Store.
Light Matter is an open-source application, you can find its source on GitHub. And features requests and bug reports are welcome and can be submitted here.