PKPASS contains 4 types of files:
Usually a file without a extension suffix; stores file’s digital signature.
Graphic files are used to display images for passes stored in the wallet.
Scripts store access settings for accounts and various pass data.
Environment files store compatibility settings for various operating systems and their versions; settings are stored in separate folders.
How to open PKPASS file?
Accessing PKPASS file contents is easy. PKPASS files are saved as ZIP archives, which means that they can be opened using any archiving tool that supports this format. It is also possible to change the .PKPASS extension to .ZIP and access file contents through the system shell.