DMG is a disk image format for Mac just like an ISO file in Windows. That means, it is possible to mount a DMG file on a virtual disk or write it to a DVD and access its contents. A macOS installation package with DMG extension enables creating bootable installer DVDs. My first experience with burning a DMG file to DVD was actually on Windows, back in 2013, when Mountain Lion was the operating system. I accidentally formatted the hard disk of my iMac and lost the recovery partition in the process. The only option left for me was buying an OS X Lion Installer disc as the Internet Recovery required a lot of bandwidth and time. Later, I found a way to burn macOS DMG file to a bootable DVD on my Windows laptop. Eventually, I restored my iMac to OS X 10.8 using the same DVD as macOS installation disc.