What is lpformnum attribute?

Question

I'm making simple html+css page and added there form without any attributes (id or class). When i view it in chrome dev tools, it shows <form lpformnum="1"> instead of just <form>. Just curious about what is lpformnum and why it's added :)

Answer 1

I am fairly positive that it comes from the LastPass browser extension. This allows LastPass to identify the form and to autofill it.