https://cabforum.org/working-groups/server/baseline-requirem...
You can also just search the document for the word "Perspective" to find most references to it.
"Effective December 15, 2026, the CA MUST implement Multi-Perspective Issuance Corroboration using at least five (5) remote Network Perspectives. The CA MUST ensure that [...] the remote Network Perspectives that corroborate the Primary Network Perspective fall within the service regions of at least two (2) distinct Regional Internet Registries."
"Network Perspectives are considered distinct when the straight-line distance between them is at least 500 km."
I.e they check from multiple network locations in case an attacker has messed with network routing in some way. This is reasonable and imposes no extra load on the domain needing the certificate all the extra work falls on the CA, and if Letsencrypt can get this right there is no major reason why "Joe's garage certs" can't do the same thing.
This is outrage porn.
Also, there are loads of other requirements except this one and they are there for good reasons. It’s not easy to get your root certificate accepted by Firefox/Google/Microsoft/Apple and it shouldn’t be.
Everywhere I've read, one "must validate domain control using multiple independent network perspectives". EG, multiple points on the internet, for DNS validation.
Yet there is not one place I can find a very specific "this is what this means". What is a "network perspective", searching shows it means "geographical independent regions". What's a region? How big? How far apart from your existing infra qualifies? How is it calculated.
Anyone know? Because apparently none of the bodies know, or wish to tell.