I built the Googlebot Tracker 4200 tool about a year and a half ago, and so far it has collected around 55,000 rows of Googlebot data on this website (Waraas.com). Interestingly, it also picked up about 50 rows of crawl data from other people's websites as well.
I honestly have no idea how the tool grabbed Googlebot data from external sites, but I did hypothesis a few different reasons why it could be happening in this blog post here.
Below you can explore the Googlebot crawl data from those other websites:
Total External URLs: 93
Ever since building my first website in 2002, I've been hooked on web development. I now manage my own network of eCommerce/content websites full-time. I'm also building a cabin inside a old ghost town. This is my personal blog, where I discuss web development, SEO, cabin building, and other personal musings.