When you need to view a PDF, the standard route is visiting the Adobe website and clicking "Download." However, IT professionals and power users often run into a hurdle: the default download is usually a small "stub" or "web installer" that requires an active internet connection to finish the job.
A. The downloaded file is larger (500MB vs 2MB). But the final installed size on your hard drive is exactly the same (~300-400MB).
For legacy versions or specific patches, technical users often access Adobe's official FTP repository.