In that case, please show me a witness transaction only Legancy inputs in the blockchain.
You were right about only legacy inputs transaction since that's what the last sentence of the quote also says. It's at the beginning of the document btw. My question now is how to construct the witness in the following case:
but what if only some of the inputs are segwit?
= segwit
Good question.
Funnily enough, I am currently busy with the same task.
When I'm done, I'll report. :-)