Splitting this out from T116353:
In T116353#1771639, @Legoktm wrote:In T116353#1771167, @Glaisher wrote:In T116353#1770776, @MZMcBride wrote:
- if you insert "Special:BlankPage" into the "Title of Main Page" text field at http://newsletter-test.wmflabs.org/wiki/Special:CreateNewsletter, the error message tells you "Special:BlankPage does not exist", where "Special:BlankPage" is a blue link; this is weird behavior
This is the default message thrown by HTMLTitleTextField from core. I have submitted https://gerrit.wikimedia.org/r/250184 for this.
It seems like this field should be setting 'creatable' => true so special pages aren't accepted?
Maybe the default value is wrong here?