[policy, no patch] Formalize how external links are handled in core

The Drupal core Accessibility → core gate states that a goal of core is to conform to WCAG 2.1. That standard has recommendations, https://www.w3.org/WAI/WCAG21/Techniques/general/G200, for this case.

There is an item here to add a sniff for target=_blank. But there are valid cases for using _blank so adding a sniff to to warn about it's use could be disruptive when running commit-code-check.sh.

Therefor, I think everything is done here.

Thanks everyone!

Changing to latest version when this was closed.

@xjm reminded me that this should be check by the Accessibility maintainers. I will ping in slack.

I think #24 is correct and we probably can't add this to the core ruleset (unless we confirm that there really is not a single valid core usecase presently). It could potentially be a DrupalPractice sniff or something.

That said, I think core is definitely using target="_blank" in a number of places it should not. We should audit and remove most if not all of them.

It looks like 📌 Target="_blank" attribute add to external links. Postponed already exists for getting rid of those pesky new windows.

Makes sense to me.

@mgifford, thank you for responding here and in slack, confirming that this core gate is correct.

I updated the IS to say the implementation is to be done in 📌 Target="_blank" attribute add to external links. Postponed .

Also restoring the outdated status.

Saving credits.