What filters can be applied to exports of Email Send Activity from Eloqua API?

My team is working on an integration that would pass Eloqua activity data - in this case email sends/opens - to a third party reporting platform. The integration gives the option to select various data activities such as "Email Opens" and then has a section where filter logic can be applied to the export of that activity.

We would like to only pass email open activity for contacts within a specific segment for specific campaigns.

I see this EXISTS('{{ContactSegment[<id>]}}') statement as an example for contact segment filter. Is this correct?

What campaign criteria can be filtered on and are there examples or a dictionary with the field names and syntax for campaign filter statements?