Some file formats are specified in terms of non-byte-aligned bitfields instead of bytes. Sometimes they even cross byte boundaries. It would be neat if one could poke at the individual fields in these files.

Examples include instruction encodings (x86 has a lot of 3-bit fields), compression formats (gzip uses 3-bit headers on blocks and it gets weirder from there), and some image formats (webp starts off with reasonable byte-aligned headers and then suddenly 14-bit image width/height fields).

I have no idea what the UI for this would look like. I think the only reasonable approach is to default to normal bytes-displayed-in-hex view, but then allow the user to break up and reassemble the bits as needed (either manually or script-assisted).