Editor Camera Skewed

Revised answer:

• Right-click on the transformation gizmo at the top right corner will reset the scene view camera to a fixed view

• Closing and reopening the scene view tab (right-click on the header label) will reset the camera to its default position

• Restarting the editor will reset the the camera

@Bunny83 noted that focusing a GameObject with the F hotkey, will not reset the camera orientation.