The link with a space is looking for pages that contain both the word link(s) and your url - eg it just a search for those words rather than a backlink check. Although of course by its nature it does check pages that probably link to you :) - but obv not all as not all pages that link to you have the word Link(s) in the text.
Your explanation seems to be right on the money. What is most interesting about this search with an empty space is that everything there seems to be junk link directories and hijacker?type 302 stuff. Everything I see has "Supplemental Listing"
Could this indicate that G is sorting out the junk links pretty well? Does anyone else see all of their dirty laundry there?