With the introduction of the new help button opening up the manual in Koha 18.11, clicking on Help when in the patron category set up in the administration module does not bring the user to that portion of the manual, instead it goes to the main page of the manual. It should go here : https://koha-community.org/manual/18.11/en/html/administration.html#patron-categories
Tested in 23.05 and it's fixed :)