To decode these, we throw away the last tx and the last constant of each input, e.g.:
btc getrawtransaction 033d185d1a04c4bd6de9bb23985f8c15aa46234206ad29101c31f4b33f1a0e49 true | jq -r '.vin[].scriptSig.asm' | head -n -1 | sed -r 's/ [^ ]+$//' | tr -d '\n' | xxd -r -p > tmp.jpg
Terminology mentioned e.g. at: Data Insertion in Bitcoin's Blockchain by Andrew Sward, Vecna OP_0 and Forrest Stonedahl.