Something what will highlight or prettyprint file's internal structure. Like hex editor, but more intelligent. It should either know most common files already, or should be configurable enough.
Something like Wireshark, but for files.
Windows or Linux is fine.
101 editor comes with "binary templates" that interpret binary files for you. The template repository contains templates for >80 binary file formats (as of today).
101 editor is a commercial product, starting at 50$ for home use and 130$ for commercial use. It's available for Windows, Mac and Ubuntu.
Screenshot of binary templates from their website:
I use my Binary Editor for this kind of task. Certainly not as pretty as 010 Editor (its a text mode program), but decodes quite a few file formats and is user extendable. http://www.nyangau.org/be/be.htm
Binary freely redistributable, but not open source.
Hachoir (https://github.com/haypo/hachoir3) is the library to consider.
It is free, open source, is written in Python, installable via pip install hachoir3.
Command-line tools using Hachoir parsers:
For docs, go to https://hachoir3.readthedocs.io/urwid.html.
Disclaimer: no affiliation whatsoever.
