Sleazy Fork is available in English.
improve UX of Gallery Page, Multi-Page Viewer and Front Page
This script is to enhance the UX of Multi-Page Viewer but not to implement it.
So you have to unlock the Multi-Page Viewer in the Hath Perk page (https://e-hentai.org/hathperks.php)
or be a Gold Star member (https://ehwiki.org/wiki/Gold_Star)
Image ref.: https://ehwiki.org/wiki/Technical_Issues
oh , I see
why Multi-Page Viewer Enhancer always display this？