this is just the Robot Browser that starts in addition to the Android emulator so that you can monitor the robot's functions and simulate voice input.
It can happen that only the Robot Browser is started, then simply close it and try to start the emulator again, two windows should always open, the Robot Browser and the Android Emulator.
You may have to try several times.
When the Android emulator is started, you should be able to see it in Android Studio, sometimes the Android Studio window has to have the focus.
Pepper Emulator is lunching but device is not detecting in linux.