https://drafts.csswg.org/selectors-4/#the-target-pseudo
The :target pseudo-class matches the document’s target elements. If the document’s URL has no fragment identifier, then the document has no target element.
The intention seems to be that a document can have multiple target elements. (HTML can only have one, but I can see CSS wanting to stay general, for whatever reason.)
If so, the last sentence should probably be "the document has no target elements".
This is causing minor confusion in https://github.com/whatwg/html/pull/1370/files/6048d915035fefd69e31f903beac6f53356e4462#r65485805