You can find it here:
https://hentaiocean.com/api-docs
It is one of those kinds of sites that gives you everything you need to start a hentai website of your own on autopilot: API, embed code, images.
Great question, it was an expired domain. It didn't have many backlinks, I believe it had ~300 weak nofollows and ~80 weak dofollows the moment I bought. Now it has +1000 dofollows, but only making $0.50/day at the time of writing (which is still good, profits).
Google deranked me at some point, but I am still happy with the project. I haven't mentioned on this thread, but I started a second autopilot hentai site with same setup but only display ads, just to try things out. That one is making $0.05/day but has a lot more visitors that return to the site. If I added pop-ups & more to that one, I would be making $2-5/day, but I am refraining from doing it at the moment.
Since Site A is making me $0.5/day (that's like 1domain per month), I have been thinking of just keep going and making more, each with different SEO strategies. This market is saturated, but Google isn't ranking the top sites on the top when searching titles directly.