The video is short, old, macOS-only, and has been unpublicized from YouTube.
The Internet Archive has it [archived in 2021](http://web.archive.org/web/20210221034604/https://www.youtube.com/watch?v=cer9EUKegG4).
Given that opening the archived site is not a very user friendly way or guidance (slow, confusion regarding missing content, YouTube reference, etc), and the intentional removal done by publishers, it seems more appropriate to drop the link.
Resolves#574
* read-me-updates
In addition to some general improvements to the text, this change focuses on adding notes about:
* checking the readme file for any limitations on domains or pages the extension works in
* the fact that no extension runs in a private window by default, with a link to related help article
* contacting the discourse forum as a first point of call for issues
* Minor changes from readthrough