The #0 represents how many times that kernel has been compiled.
If you manually compiled the kernel, the first time installed it would be #0. If you recompiled it and reinstalled, it would then show #1. Recompile and re-install, and it will show #2. And so on.
The number in front of the kernel name (4.5) is the OS version.
In BSD land, the OS version and the kernel version are always the same, as they are developed as a single, integrated unit (you don't "upgrade the kernel" without also upgrading the entire OS).
|