This will show you a room's info including any fields that are only visible to opers, such as marks.
Example:
/msg chanserv info #spiderslair
Whenever you do an info command while opered it will show you the additional information only available to opers. It is generally good to info a room if you are dealing with it in almost any way. While usually there won't be much interesting, you might notice something that you will find helpful.