Notes about the IPSW file extension:
To open this file type, a required software must be installed. Without it you only see a Windows message "The following file cannot be opened
" (Windows 7) or "How do you want to open this file?
" (Windows 10) if you double-click the file. There click on "More apps"
and choose a suitable software to view such files on your PC or from email attachments.
The IPSW file type is primarily associated with 'iPhone/iPod' by Apple Inc.. This is a firmware update file for the iPhone. The file is a renamed .ZIP file. If you unZIP it you will see a file called MANIFEST.PLIST and a file without an extension but with a version number in the name, e.g., Firmware-14.5.3. This file is the firmware image.