Is public free/busy information useful?

[Cornelius Hald]

Hi,

I was just wondering whether or not it is a good idea that the free/busy
URL is accessible from everywhere.

As far as I understand the Roundcube calendar is using it to check
whether or not invited people and resources are free or busy. But is
there also something like a internet standard that defines how other
calendar clients resolve that URL? So that Evolution, Outlook, etc.
could query that information as well?

If not, that URL should probably be only readable by roundcube, right?

Thanks!
Conny