Can I have non-boolean TargetBlank output using HTMLPurifier and the Redactor plugin?

Question

I'm using the Redactor plugin throughout a Craft 3 site and I'm also using a custom HTML Purifier config to clean up the HTML (surprise).

{
  "HTML.ForbiddenElements": [" ", "br"],
  "AutoFormat.RemoveEmpty.RemoveNbsp": true,
  "AutoFormat.RemoveEmpty": true,
  "AutoFormat.Linkify": true,
  "AutoFormat.RemoveSpansWithoutAttributes": true
}

However it looks like it overrides Redactor's link target blank option and that override is either on (open in new tabs) or off (strip target blank).

Is there any way I can give that choice back to the user? Maybe I can stop Craft using the full url for links other than external links?

Answer 1

And this solved the problem:

"Attr.AllowedFrameTargets": ["_blank"]