Its a hex editor built with imgui and has a lot of built in tools. Imo the best feature is the data structure editor. You can write a data type definition similar to C and it overlays it on the hexdump and parses it in a structured way while you type.
It also has a node based editor.
How many rules would it take to create 256 different colors for 00..FF?
But - it's also kind of huge for a hex editor. Wouldn't it be overkill for most people?
It really is by far the best hex editor I ever used, and sooo good for reversing arbitrary binary blobs where you learn incrementally more about its structure while reversing it. The imhex patterns repo [1] also contains so many formats, it makes binwalk almost useless in comparison.
This is another fine tool I can add to my collection.
And FUTO! Love it.