Board Thread:Support Requests - Getting Technical/@comment-30509676-20190729200550/@comment-27958705-20190730021725

it is vector skin. that successor of monobook. on dev wiki was a script, that converted monobook to pseudo-vector. but now there is no monobook anymore.

the most close thing u can have is PseudoMonobook stylesheet. if u experienced in css and js, u can create ur own pseudo-vector. but u will not be able to use it sitewide. it would be tou violation. that makes investments into the research something not so useful.