Hi, you're welcome.
It's the private active key of the account you'll be using as a witness. So it is one of the infamous four Hive key pairs :)
Manage Witness button.You put the public active key in the form here (https://tribaldex.com/witnesses) by clicking on the
There you can also enable / disable your witness node.
The same can be done via script by calling:
node witness_action.js register
or
node witness_action.js unregister
Good luck.
Hive Engine Script Updates.Also, check @blervin's latest post.
Good luck!