Function difft::files::guess_content

pub(crate) fn guess_content(
    bytes: &[u8],
    path: &FileArgument,
    binary_overrides: &[Pattern]
) -> ProbableFileKind

Do these bytes look like a text or a binary format? If it’s text, decode it.

This is based on heuristics: we look for well-known binary format headers and then try decoding in several different text encodings.

git-diff itself has a smaller set of heuristics, looking at whether the bytes are ASCII or a superset of ASCII (UTF-8, ISO-8851-1) unless working-tree-encoding is configured with .gitattributes.

https://git-scm.com/docs/gitattributes#_working_tree_encoding