Why does GNU Diff not understand Unicode (only UTF-8)? : Why does GNU Diff not understand Unicode (only UTF-8)?

This GNU Diff is used by default in Git.

Why this bug does not fix?

BOM is part of the Unicode standard. http://www.unicode.org/faq/utf_bom.html#bom4

Why is BOM ignored by most programmers?

In Windows, the encoding of UTF-16 is used by default for some source files.