At https://kissmanga.com/BookmarkList when I hover any title I can't see tooltip with image representing logo of the manga.

Tooltips are removed by this fragment of script:

$('body>div[style*="absolute"]').remove()

To prevent tooltip removal we can modify that part to ignore .tooltip class

$('body>div[style*="absolute"]:not(.tooltip)').remove()

Tested on Chrome and FF.

Other solution could be using jQuery instead of CSS like .not(selector):

$('body>div[style*="absolute"]').not('.tooltip').remove()

Cool, thanks! I'll add this.