I wish there was a less email-centric workflow to contact the HN mods, because I think your link is much better than a sign in page for showing off the intended content
That page is available by clicking the link that says "Explore groups and projects" on the page that is linked in this post.
Yes. Open source is about being able to modify and redistribute code for the products you already have access to. It's not about just giving everything to everyone.
The GPL allows you to not publish the source, as long as you provide it on request. Several older “open source” projects were distributed exclusively by CD-ROM.
Is it really open source if there's no repo at all? Absolutely
It’s perfectly valid for someone to just release tarballs of their source code releases. You don’t need a bunch of infrastructure to share software.
It's a discoverability problem of that particular page; as a sibling comment mentioned, it's possible to view the public project, it's just that this site has no link to /explore - just /search from what I could see.