I'm using an SEO plugin for my web browser called SEOquake and I'm trying to figure out what all the options mean. I'm looking at one result here on google that says the page has a PR of 4, yet they have 0 SEMrush links (which I'm assuming are just links to that page). Then beside that it says SEMrush linkdomain. Does that just mean links for the whole domain overall? If so, should that page really be ranked that high even though it doesn't have any links going to it?