For programming language sourcefiles yes, extensions help and are commonly used. To enforce extensions in 100% of all computing cases - absolutely not.
The advanced heuristics is used for additional cases such as `/usr/bin/some_tool` \- for running the stuff, I don't need to know if it's a compiled binary, bash script or Python (or Nim, in the future?) or a symlink, I want to run `some_tool`. But I'd love `file` to tell me what it is, if I need to.
