Learn about the Hidden Applications page:

To remove noise, Torii gives you the option to Hide an application. Once hidden, the application will no longer appear in Torii lists or searches, but is still considered active, and data continues to be gathered for it. 

The hidden applications page serves to store these applications out of the way, where they can be un-hidden if needed. (For more on how to hide an application, see Hiding Applications.)

The Hidden Applications settings page shows the application's name, date it was hidden, and who hid it. On hover, each entry will display a button to un-hide the application:

Note: Hiding an app will not affect any associated matching rules or contracts - these will need to be manually adjusted or transferred to another app.