Advanced List Header Fields - accessible in form action logic block?

I have an app built over an Advanced List. In the list view, I plan on adding a Form Action. Will the values in my header fields be available in the logic block?

In the below screenshot, the Stack field is the header field whose “b…Solns” value I need access to in my logic.

Yes, form actions do have access to what is in the advanced list header.

Is that just in the data source passed in?

Yes, it is what is sent up as part of the logic block payload.

@joeyates23 Is this also true if the header field is hidden?