Does "Save mtdblock contents" use nanddump?

in wiki of openwrt ( it is written that to save partition we shouldnt use dd or pv because openwrt uses whole flash as raw storage (doesn't use blocks) so " you MUST use NAND-aware tools like nanddump and nandwrite instead of the more common dd tool to create or restore a backup of the flash partitions on NAND"

but when I search luci github source for nanddump I see nothing.

and I cant find the part that does the backup.

can someone point me to the part that does the back up in luci code?
or am I missing something?