How disable this strange gizmo?

Hello, everyone.

There is a strange gizmo. Can anyone tell me what it is?

before i disable all gizmo:

after i disable all gizmo:

p.s. my hierachy is empty.

It’s pathfinding/navigation.
These instructions are version-specific, but hopefully they’ll lead you down the right track anyway:
Go to Window>AI>Navigation, navigate to the Bake tab and select Clear.