How can I customize FreeBSD Boot loader?

[fbsd_]

We are seeing a menu with FreeBSD logo and FreeBSD ball devil on boot. I want to change codes that running when we select a boot option. I already checked /boot. I saw menu.rc and loader.rc but I want to change codes that running when selected an option. So how?

Some information about my system:
FreeBSD 12.2
x86_64

 

[zirias@]

Maybe you should start with what you need. What option are you missing, what should it do?

 

[fbsd_]

Maybe you should start with what you need. What option are you missing, what should it do?

I want it to back up system every time I open with snapshots.

 

[fbsd_]

freebsd-src/stand/forth/menu-commands.4th at main · freebsd/freebsd-src

The FreeBSD src tree publish-only repository. Experimenting with 'simple' pull requests.... - freebsd/freebsd-src

github.com

Maybe I can modify that commands.
or this one:

freebsd-src/stand/lua/menu.lua at main · freebsd/freebsd-src

The FreeBSD src tree publish-only repository. Experimenting with 'simple' pull requests.... - freebsd/freebsd-src

github.com

 

[SirDice]

The FreeBSD loader(8) of 12.2 uses LUA, not the old Forth loader.