Round edges than smooth the mesh

Hello everyone!.
In my work in NVIL get great thing. I made something with edges by Draw Mesh and with snap to edges and... suddenly my edges became are rounded. it was Wow!!. But I don't know how I made it.

Perhaps someone know how make these round edges?

I worked in standard  ( default) interface.

You may have hit the "Toggle Subdivision" command tool hotkey by accident.
To Exit subdivision, Geometry > Subdivision > Level_0.

Thank you!. I'll try to make it again