pub const EMPTY_TREE_SHA: &str = "4b825dc642cb6eb9a060e54bf8d69288fbee4904";Expand description
Canonical git empty-tree hash. Callers without a prior cursor pass
this to get “every entity in the current state as added”. Both
the git-branch backend (special-cased to bypass rev_parse) and
any future folder-backend implementation honour the same sentinel.