It is the small pin for NOMAD. It is used to hold the mounting more tight. Please use the small wrench coming with NOMAD or the small wrench coming with laser to tighten it from the backside of the plate like how you tighten the ballhead.
please check how to use it here:https://drive.google.com/file/d/18epOp5qvmJWiziOmrFgwaUaM08n2gaF7/view
Please feel free to contact us (firstname.lastname@example.org) if you have more questions.