It’s HP’s official shortcut to the HP PC Hardware Diagnostics tools — specifically the download and information page for their diagnostic software (Windows, UEFI, and USB versions).
I couldn’t directly access or “review” the live webpage at www.hp.com/go/techcenter/pcdiags in real time, but I can tell you what that URL is and what you should expect based on HP’s known support structure. www hp com go techcenter pcdiags