GIT_ATTR_UNSPECIFIED checks if an attribute is unspecified. This may be due to the attribute not being mentioned at all or because the attribute was explicitly set unspecified via the ! operator. For example, if the attribute file contains: *.c foo *.h -foo onefile.c !foo Then for onefile.c looking up attribute "foo" yields a value with GIT_ATTR_UNSPECIFIED(value) of true. Also, looking up "foo" on file onefile.rb or looking up "bar" on any file will all give GIT_ATTR_UNSPECIFIED(value) of true.