WGBH is a public television station that is located in Boston Massachusetts,
The Sign Off featured the Mission Statement like normal, after that, it shows a Number 2 in a white color, on the bottom left, it has someone sweeping, and on the top of the screen, it shows Studio lighting,
Unfortunately, this has been lost media for over 46 years, The only surviving footage of it is an audio recording of the sign off, But the ending has been lost, the last 2 words of the sign off was, "...saying goodnight"
However, someone did reconstruct this sign off, and here it is: