Ask HN: How to get ISP Outage data?

Hi, I'm working on an open source project where I'd like to incorporate ISP outage data. This service claims that it reports accurate ISP outage data, that is not crowdsourced like downdetector: https://www.thousandeyes.com/outages/faq

Quote: "Q: Where does outage data come from?

A: ThousandEyes agents located across the Internet perform billions of measurements each day, yielding a massive data set that includes network interface and application server-level information on when and where network traffic is disrupted and applications are unavailable."

Anyone wager a guess on what websites they are scraping, and what measurements they are making to come up with this data?