When checking settings of custom labels in Google Inbox, one can see the filters that are used to put emails there. However, such setting is not available for the special labels e.g. Purchases, Finance, Updates, etc.
Now, I do realize that there is a classifier underneath (unlike custom labels), but when an email is moved to the label, you are still being asked if all emails from this address should be moved there. It would be good to see which addresses were marked this way. Is it possible?
Best Answer
Try these in the search bar(with clicking on the category name on the left side):
category:updates
category:forums
category:social
category:promotions
Three special category:
category:^smartlabel_receipt
category:^smartlabel_finance
category:^smartlabel_travel
Smart category is an experimental function of Gmail, seems no longer maintained.