bdisk/docs/manual/faq/GETVERSION.adoc

How do I get the version/build of an ISO?

This can be found in a multitude of places. The full-size ISO file should have the version right in the filename. If you want more detailed information (or perhaps you renamed the file), you can mount the ISO as loopback in GNU/Linux, *BSD, or Mac OS X/macOS and check /path/to/mounted/iso/VERSION_INFO.txt. Lastly, within the runtime itself (especially handy if booting via iPXE), you can check /root/VERSION_INFO.txt to get information about the build of the currently running live environment.