Googlebot

Google. It names itself with the token Googlebot in its user agent, in a smartphone and a desktop version. Google indexes mobile-first, so most fetches come from the smartphone version.

It finds pages through links and sitemaps and fetches them for Google's index. Other Google machines carry their own names: Google-InspectionTool runs Search Console's live tests, and Google-Extended is a robots.txt token for Gemini training, not a separate crawler.

Yes. Google renders pages with an evergreen Chromium after fetching them, sometimes days later, and indexes the rendered result. Content that appears only after a click or a long wait may not make it into the index.

Run a reverse DNS lookup on the visiting address. The name should end in googlebot.com, google.com or googleusercontent.com, and a forward lookup of that name should return the same address. Or match the address against Google's published list.

common-crawlers.json, Google's IP list

Rules under User-agent: Googlebot apply to it. It honors Disallow and Allow and ignores Crawl-delay. Blocking it removes your pages from Google Search.