Why does the application create 2 icons in the menu?

Question

Android

The essence of the problem is this, I study and experiment with android studio.
1. I made a build of the application
2. I downloaded it to the phone and installed
Everything is fine, everything works as I want. But when I open the menu on the phone, for some reason I see 2 icons from the application. One application and two icons.
Where to look for the devil? Mobile glitch or somewhere specifically error.

Answer 1

Where to look for the devil?

know where! in the manifest!