The .iso file extension indicates that this is an ISO image file, which is a type of disk image file that can be used to create a bootable media (like a CD or DVD) or can be mounted as a virtual drive.
Adaptive Security Appliance for firewall and security labs. cisco cml 2.5 refplat_p-20230117-fcs.iso
The term refplat_p-20230117-fcs.iso seems to refer to a specific reference platform image for Cisco CML. The naming convention suggests: cisco cml 2.5 refplat_p-20230117-fcs.iso