Problem/Motivation
The cURL link in the error message opens the external site in the same tab, replacing the current Drupal site. This can be confusing, especially for content managers as they need to hit the Back button to find their Drupal site.
Proposed resolution
Looking at other UI pages (Status, Extend, etc.), this seems to be the norm. This is not to say that it is right but at least, it seems consistent with the rest of the UI. I personally would prefer that external references open in a new tab or new window.
I think this issue can be closed for the time being.
Remaining tasks
Needs to be reviewed
User interface changes
API changes
Data model changes
Original report by [elachlan]
The cURL link in the message opens the external site in the same tab, moving away from the current Drupal site.
See attached screenshot.

Comments
Comment #1
elachlan commentedretagging.
Comment #2
elachlan commentedComment #5
christian_m commentedComment #12
quietone commented@elachlan, thanks for the report!
A policy issue has been opened to discuss this problem, #2702881: [policy, no patch] Formalize how external links are handled in core and is still in discussion. When that is resolved all the links in core will be examined to ensure they agree with the policy. Because of that I think this can be closed (as is stated in the IS). I think the best fit is closed (works as designed).