That icon, at least as I've used it and seen it used, isn't necessarily to denote an external link; it's to indicate a link with a _blank target that opens a new tab. It's a hieroglyph for "open in new window".
The long-time most prominent use is on Wikipedia, where it indicates external links and does not open a new window.
https://en.wikipedia.org/wiki/Wikipedia:External_links#How_t...
Random historic example: https://web.archive.org/web/20150105003618/https://en.wikipe... (“HyperTIES system”)
The long-time most prominent use is on Wikipedia, where it indicates external links and does not open a new window.
https://en.wikipedia.org/wiki/Wikipedia:External_links#How_t...
Random historic example: https://web.archive.org/web/20150105003618/https://en.wikipe... (“HyperTIES system”)