Why name extension of header file is hh?

[bkbits]

Why name extension of header file is hh?

[btwael]

I generally use ".h" and ".c" for C files and ".hh" and ".cc" for C++ files, I just don't like the idea of C and C++ headers having the some extension. In fact, Github sometime miss-classify C++ header as C header. I guess it's fine to do so, all editors recognize ".hh" and ".cc" as C++ file, Github too.