Constant MAX_REF_NAME_BYTES 

pub const MAX_REF_NAME_BYTES: usize = mkit_core::refs::MAX_REF_NAME_BYTES; // 512usize

Longest ref name, in bytes: SPEC-REFS §3’s bound, mkit_core::refs::MAX_REF_NAME_BYTES. It bounds every ref key (store::keys) below MAX_KEY_BYTES, with room for the longest repo name; store::keys asserts that at compile time. Clients check the same bound (mkit_rpc::MAX_REF_NAME) before sending.