Page tests are run using Lighthouse 8.0 and Chrome 91, on a headful Chrome instance.
Settings like network speed and CPU speed depend on the device selected to run the test.
By default, DebugBear send this user agent string on desktop:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36 Chrome-Lighthouse DebugBear
And this one on mobile:
Mozilla/5.0 (Linux; Android 7.0; Moto G (4)) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Mobile Safari/537.36 Chrome-Lighthouse DebugBear
Note that the Chrome version is based on what's specified in Lighthouse, not the actual Chrome version that's used to load the page.
Read this blog post to learn more about how different settings and environments can affect your scores.