Function read_conduit_original 

async fn read_conduit_original(
    source: &MediaSource,
    depth: u8,
    length: u8,
    sha256: &[u8],
) -> Result<Option<Bytes>>

Reads one Conduit original, named by its content digest, from the configured media source. A filesystem file that cannot be read is reported as None (skipped, like a dangling metadata row). A source storage provider is retried on a transient fault; a persistent one returns Err so the import aborts instead of dropping reachable media.