Yes, it's not essential. It's just telling you that you don't need the slash, that it may create problems in some circumstances, but there are no problems on the page that was just checked.
I think attributes should generally be quoted, even in situations where you don't really need to quote them. Apart from anything else, it saves you having to remember all the rules for when you can and can't get away with not quoting them. It's also good for clarity, IMO.
Mannix_ wrote: ↑Sun Oct 16, 2022 10:20 am
those links are added by the extensions. So I would look in there. To be precise in the ext/extName/styles/styleNameThatYouUse/template/event