I was trying to add a Wiki page to a tag here on meta, but I have problems to create it: when I click on the button to create it, nothing happens.  
I also tried to edit an existing tag Wiki, but again I could not do that. Clicking on the edit link that appears in the pop up associated with a tag takes me, e.g., to https://drupal.meta.stackexchange.com/tags/discussion/info, where I see the "Edit Tag Wiki" button; when I click on that button, nothing happens.