Function git_path_relative_component 

pub fn git_path_relative_component(path: &str) -> &str

The relative portion of a --git-path argument, mirroring how Git builds the buffer in repo_git_pathv: the caller-supplied fmt string is appended to <git_dir>/ verbatim and only cleanup_path runs over the whole buffer. In practice that means a single leading / (and a leading ./) is dropped from the user-supplied component while internal // runs are kept intact.