[tex-live] please clarify tlmgr generate

[Maxwell, Adam R]

Can someone please clarify the following sentence in the man page for tlmgr?
This refers to the `generate updmap` action, but I can't figure out what
it's supposed to mean.

"For "updmap", however, "tlmgr" use "generate", because the result would be
to disable all maps which have been manually installed via "updmap-sys
--enable", e.g., for proprietary or local fonts."

thanks,
Adam