Function classify_git_tree_name 

pub fn classify_git_tree_name(
    raw_name: &[u8],
    at_root: bool,
    symlink: bool,
) -> Result<GitTreeNameClassification, ReservedMetadataName>

Classify one Git tree entry name for import. at_root says the entry is a direct child of a commit’s root tree, where .heddle is reserved too; symlink says it is a symlink, which .gitmodules may not be (see reserved_tree_entry_name).

A reserved name is an Err: import must fail, and not even --lossy may drop it, because the tree is hostile rather than unrepresentable.