Apart from the usability issues, currently the pattern field is (justifiedly so) escaped to prevent SQL injection. However, the way it is does not allow any pattern characters in the pattern, only exact match, making the field pretty much useless.
Verified on https://www.mediawiki.org/wiki/Special:Nuke
Steps to reproduce:
- Find a new page title in https://www.mediawiki.org/wiki/Special:NewPages (open a page, copy the title from the URL so that you have the underscores, for instance Wikimedia_Developer_Summit/2017/Room_Setup).
- Enter the title in the pattern field at https://www.mediawiki.org/wiki/Special:Nuke and submit.
I. Observed: The page is found and selected for deletion.
- Repeat (2) with a truncated title and % wildcard (e.g. Wikimedia%).
II. Observed: the form is reloaded with an error message "there are no new pages in recent changes" and the field gets emptied.