pkzip password

[chants]

On the github you can read example/tutorial.md. it answers this: https://github.com/Aloxaf/rbkcrack/blob/master/example/tutorial.md

So you need to check if the XML is stored or deflated. If its stored you can easily use your 12 bytes of plain text to crack it. If its deflated the attack is no longer practical and you are better off hunting the web for the full XML file. Also some XML files can have UTF byte markers or even non standard white space at the start, not all are clean xml. Something else to consider.