How to retrieve a vault ID?

I am currently developing an extension to Cryptomator to be able to use a specific board that generates and store passwords.

whether it is creating a new vault or accessing an old one, I need to send the vault ID to my board so that it checks if it is stored inside of it or save it if its creating a new one

How can I access this vault ID? which class/variable is it under?

Thank you in advance