Not that it's a real issue, but the 2nd page on the popular tab is actually not a pdf at all. I assume it appears because the url (<a href="https://mango.pdf.zone" rel="nofollow">https://mango.pdf.zone</a>) contains ".pdf" within it?
I love 1-purpose web sites, like 1-purpose CLI utilities like `ls`. It's really fast and looks nice, IMO. I think it's also a good idea: the PDFs on HN are usually a bit more oriented towards tech and interesting computer science than the articles, which can be peppered with political posts and such. Filtering by PDF link will likely result in a more educational feed :)
This is nice. I often find myself trying to recall specific HN links for a variety of discussions.<p>Just recently, a PDF link was one of those. This site made it very easy to find again. Plus, many comments had been added since I first saw it on the front page. Nice work!