No, it is based on the simple @mention in the caption or @tag in the picture
At the moment the official Paid Partnership tag is not open to all brands and all influencers. Most of the micro-influencers have no access to such feature and therefore it can not be used as global method.
Some western countries passed laws requiring influencers of all sizes to use the proper hashtags to indicate they are doing a sponsored collaboration. For example #ad,#sp,#sponsored,#collab
However the number of countries where this is enforced is very little and also in those countries many influencer are not complying.
For all these reasons, filtering the results either by Paid Partnership or by Hashtag would produce unreliable results, with many posts missing. Popular Chips thus decided to provide the complete list of @mentions and @tag to offer a complete overview of the influencers' collaborations.