Some help texts contain links to an external site. Currently, the links open in the same tab/window.
The user might lose changes by navigating away from the form in the same tab/window.
Although WCAG states that "Opening new windows and tabs from a link only when necessary", an exception exist that "Opening a page containing context-sensitive information, such as help instructions [...] will significantly disrupt a multi-step workflow, such as filling in and submitting a form, if the page is opened in the same window or tab."
Steps to reproduce
Go to, for example, /admin/config/people/accounts.
Click "Browse available tokens."
Expand "Current date"
Click on the link "the PHP documentation"
An external site opens in the same tab/window.
Proposed resolution
Open help links in a new window.
Notes
This issue was brought up during a user research session of the site I'm working on.