Approval Process - flow as an action

Hi 

I've noticed  that  actions (initial, final, step ) for approval proces now include Flow.

I can't find anything about this in  the documentation that still mentions only the other 4 actions. 

Does anyone know what flow type is needed to be selectable? 

I've created an autolauched flow and it's not visible. Nor are the record triggered flows for this object. 

thanks for help