Inside scripts sometimes you need to push an arbitrary length of bytes on top of the stack. Example: pushing public key after signature inside scriptsig. In these cases you use special operators called OP_PushDataX
or OP_PushBytesX
telling the interpreter that X
number of bytes should be pushed to the stack. You won't find these names in any library because there isn't any. Basically we interpret any value from 0x01 to 0x4b as a OP_PushDataX
operator. Remember that every operator is just a single byte starting from 0 to 255 each performing a different operation.
So in your example which is a scriptPubkey for P2PKH outputs you want to push the result of Hash160 hash of public key (which is 20 bytes) on top of the stack so you include 0x14 (=2010) before the actual bytes. And the script becomes:
OP_DUP OP_HASH160 OP_PUSHBYTES_20 [20_bytes_here] OP_EQUALVERIFY OP_CHECKSIG