Yeah, but back in the day you didn't run the raw square wave signal into your headphones. Even if you used headphones the beep would go to the speaker either in the chassis or in the monitor
That's the true-to-life sound of the monochrome monitor. Bonus points for added realism!
Wish I've read the comments before opening the link.
This didn't happen for me, chrome on Linux. I was listening to Jimmy Dore in another tab, and there was no high-pitched sound.