Constant HEADER_FINAL 

pub const HEADER_FINAL: &'static str;

HTTP header marking an upload request as the FINAL chunk of a file.

When present (value 1/true), the server verifies that the resulting file size equals the declared x-libfw-file-meta size before committing, so a client cannot commit a truncated file. Absent (older clients) skips the check — the header is optional and backward compatible.