Constant MAX_MANIFEST_BYTES 

pub const MAX_MANIFEST_BYTES: u64 = _; // 1_048_576u64

Byte cap on one manifest object.

A manifest describes a single segment copy, so a real one is a few kilobytes. The cap is what stops a hostile archive from making the verifier buffer an arbitrary object: [read_capped] issues a HEAD first and refuses an oversized object before it reads a byte of it.