'link' and 'meta' are void elements in HTML5 and are forbidden to have end tags.
https://www.w3.org/TR/2011/WD-html-markup-20110113/syntax.ht...
https://www.w3.org/TR/2011/WD-html-markup-20110113/syntax.ht...
I was coincidentally checking the same thing yesterday, and yes, '/>' is optional.