GitHub repository: ronaldoussoren/macholib
Primary language: Python
Description: macholib can be used to analyze and edit Mach-O headers, the executable format used by Mac OS X.  It's typically used as a dependency analysis tool, and also to rewrite dylib references in Mach-O headers to be @executable_path relative.  Though this tool targets a platform specific file format, it is pure python code that is platform and endian independent.