Google Pixel Digital Wellbeing - How does it measure the usage of the applications?

I noticed that many applications are logged as part of **today usage** in Digital Wellbeing dashboard app, even though I have never opened those app for today (for example). I read [google documentation](https://support.google.com/android/answer/9346420?p=wellbeing_site&visit_id=637504389302044561-1193720974&rd=1#zippy=%2Cfind-out-how-much-time-you-spend-in-apps%2Climit-how-much-time-you-spend-in-an-app-each-day) and it doesn't really describe the details. My concern is + **Do those applications automatically running on background even though user doesn't use them?** (or) + **It is because of how google measure the activity?** Has anyone experience these before?