Where to download Blender's complete package? Where do I go to download the whole install package, e.g., blender-2.80-50ccbe6bb233-win64?

I assume Blender will update again, and I do NOT connect my workstation to the internet at all, nor my powerline directly.
Every download of Blender is complete and works offline, not matter if it's the installer or archive version. Also Blender doesn't auto-update, updates need to be installed manually.

If you're looking for a build from a specific commit (hash), you'll have to build Blender yourself. Once you've cloned the git repository you can revert to the commit hash you want to build.