>In this case an API would be more up-to-date, and less computationally expensive than serving large, always-changing lists.
Like Google search?
I fail to see whats hard about returning a large list of items. Its their entire organizations' core competency.
https://transparencyreport.google.com/safe-browsing/search
Makes you type-in a single URL. There is no way to use a keyword to get a list of items back. My point is that it should be trivial for google to do this, since this is their core competency.
I fail to understand whats so special about maintaining a tiny list of website URLs that anybody can access at any time? I'd wager you can fit 10+ million URLs per GB. The wayback machine has 300 billion+ pages of full page historical content and you can access all of it. This is entirely within Google's wheelhouse. Certainly, there could be other factors to not handout the list, but I'm merely speaking about the engineering aspect here.
Oh please. Claiming Google can't publish a giant list is really disingenuous. The question is really if they want to or not.
My guess would be there isn't a simple canonical list, and it's more of a heuristic evaluation where certain thresholds will trigger site warnings.
In this case an API would be more up-to-date, and less computationally expensive than serving large, always-changing lists. It was likely just the more logical choice. Though I'm assuming the new ads functionality uses the same Safe Browsing infrastructure.
>Sure they can say they don't want the offenders to know they are offending
Actually not the case at all. They send alerts to sites that are affected by Safe Browsing via Search Console.