Constant MAX_DBMD_FILE_BYTES 

pub const MAX_DBMD_FILE_BYTES: u64 = _; // 67_108_864u64

One db.md text file is bounded before allocation/YAML parsing. Interactive records are intentionally small; a larger blob belongs in the asset layer. This prevents a hostile path or imported store from making every read, validate, or format operation allocate an unbounded string.