The coinbase must be between 2 and 100 bytes long and must be valid when deserialized as a "CScript", but may contain arbitrary data.
Block 158479 looks like it is doing merged mining.
The '07456c6967697573' at the start is the string 'Eligius'.
The stuff in the middle looks like hashes for other block chains.
And the '074f505f4556414c' at the endis is the string 'OP_EVAL'.