If you click on the Mobile Time Tracker oAuth tile on the App Launcher, you will see a Thank You page like in the image here.
Unlike other apps, all that Time Tracker uses the tile is to get the oAuth privileges for using the Time Tracker for Salesforce app. You only need to click on the tile once, when you initially install the Time Tracker for Salesforce app. If you click on the tile again, your app just gets re-authorized. Nothing else happens and the Time Tracker for Salesforce continues to work as usual.