On the Download page there is a section "Verify your Download."
To verify the SHA256SUMS.asc I need a GPG public key, but I cannot obtain this key through the instructions given on the site, as link builder-keys/keys.txt yields a 404.
This was fixed in #964. We've been having some issues getting the build server to sync with the web server, hopefully that will be fixed and the changes live later this week.
On the Download page there is a section "Verify your Download." To verify the SHA256SUMS.asc I need a GPG public key, but I cannot obtain this key through the instructions given on the site, as link builder-keys/keys.txt yields a 404.