MacOS
...well, here we go. First complaint is against Google and just about every website and person that writes about MACs. Why? Straight forward answers. Below are some examples;
What Directory are macOS Operating System Upgrades Stored in when Downloaded from the "App Store"?
Finder Answer: Applications
Terminal Answer: /Applications
What does the .APP File Extension Indicate?
Normal Answer: An Application Bundle
Real Answer: It's actually a Directory that contains other Directories and Files
Windows Answer: .APP is sort of equivalent to .CAB Files, but more accessible.
Linux Answer: .APP is sort of an equivalent to an .RPM, but more and less.
How Can You Create an USB Drive with the Installer (.APP Files and stuff) on it?
See: https://support.apple.com/en-us/101578 (thanks Apple)
Other Useful Links
List of Apple OS's to Download or "AppStore Install": https://support.apple.com/en-us/102662