Picture-in-picture permission allows an app on the Huawei smartphone to show itself in a pop-up or floating window over another app.
An example would be to show a video while writing an SMS in the news app. This permission can be granted or revoked at any time.

Android 10 | EMUI 10.0
Picture-in-Picture -  Open the  Settings
Picture-in-Picture -  Tap on  Apps
Picture-in-Picture -  Tap on  Apps
Picture-in-Picture -  Open the  menu
Picture-in-Picture -  Tap on  Special access
Picture-in-Picture -  Tap on  Picture-in-picture
Picture-in-Picture -  Choose an  app
Picture-in-Picture -  Enable or disable  Allow picture-in-picture
  1. Open the Settings
  2. Tap on Apps
  3. Tap on Apps
  4. Open the menu
  5. Tap on Special access
  6. Tap on Picture-in-picture
  7. Choose an app
  8. Enable or disable Allow picture-in-picture

Huawei Instructions