Is there any opcode update details? For example, string link opcode?
As the big text you just quoted states, a new OP code called OP_CHECKSIGADD is added to replace OP_CHECKMULTISIG(VERIFY) working with Schnorr signatures.
Apart from that the behavior of OP_CHECKSIG is also changed if it is inside a Taproot script as it needs a different sighash and treats signatures as Schnorr signatures not ECDSA.
There are also some small changes such as OP_(NOT)IF mandate "minimal if" (the item popped by the operation has to be empty array or 1).
Thank you very much for your reply. I have two questions here. The first one uses Bitcoin script to implement string concatenation in the stack? I did not find a valid opcode in the latest Bitcoin script? Second, how can I better learn the Bitcoin script, or can I recommend some good information?