IPSWs are restore images that were exclusively used by Apple’s iPhones and iPads to install the operating systems on to devices that were in states that required it through applications such as iTunes and Apple Configurator.
With the transition to Apple Silicon from Intel CPUs, Macs now use the same ARM architecture that historically only iOS devices uses and also now utilize IPSWs when you need to restore the operating system on Macs that are in “troubled” states. What macOS IPSWs can also be used for are the creation of VMs. This is helpful for development and other types of testing when using Apple Silicon Macs. Below are links to IPSWs that can be used for either purpose from macOS Big Sur (the first version of macOS compatible with Apple Silicon Macs) to the latest version of macOS (currently Ventura). They are all from Apple’s Content Delivery Network.
macOS 13 Ventura
macOS 12 Monterey
macOS 11 Big Sur