Apparently brave search gets a hard time yielding almost no relevant results with -webkit-box-reflect as well.
<a href="https://search.brave.com/search?q=+-webkit-box-reflect" rel="nofollow">https://search.brave.com/search?q=+-webkit-box-reflect</a><p>Edit: Google yields no results as well
<a href="https://www.google.com/search?q=-webkit-box-reflect" rel="nofollow">https://www.google.com/search?q=-webkit-box-reflect</a><p>I've concluded that the dash symbol most likely has some kind of operator role similar to double quotes for example.