Feed OK (200), but from where?

Hey, so a slightly weird question, how is NewsBlur checking this feed for updates?

Feed link http://canada.pch.gc.ca/eng/rss?searchFilter=008: 200
Website URL http://canada.pch.gc.ca/halfmastingnotices_eng: 404

I don’t see an A/AAAA/CNAME record for that host record, and in fact it did change. In typical government fashion they couldn’t be arsed to notify anyonie about the change, and unfortunately because NewsBlur is updating the feed from somewhere, it didn’t show as broken so I didn’t notice it.

No big deal, but it has me wondering where NewsBlur is getting the 200 and 404 responses from given that the hostname does not resolve.