In the top-right corner of the Special:NewPagesFeed there should be a "Help" link, as is standard on most Special pages.
Compare with:
- https://meta.wikimedia.org/wiki/Special:Log
- https://meta.wikimedia.org/w/index.php?search=foobarbang
It should link to the existing Enwiki docs page at https://en.wikipedia.org/wiki/Wikipedia:Page_Curation/Help
Technical Docs: https://www.mediawiki.org/wiki/Help:Page_status_indicators#Using_indicators_from_PHP_code