Pkg Viewer -

If you are referring to standard Apple installer files, you do not need a special "viewer" app. You can use the built-in option in the macOS installer to see what will be installed before you run it. Alternatively, the command-line tool pkgutil --expand file.pkg output_folder can be used to unpack them.

: Checks if a package is a "Fake PKG" (fPKG) or an official retail package. PKG Viewer

: Displays the unique Title ID (e.g., CUSA12345 ) to ensure a game and its update share the same ID and region. If you are referring to standard Apple installer