In 'Units & Rates>Rate Management" it is possible to see which room categories you have available in channels and on your website. 

For each room category and day there is a number, this is the available number of rooms.

If there is any restriction added to the day this will be displayed shown in 3 different ways; either the availabilty number will be blue, there will be a stop icon or there will be a rules icon.

If the availabilty number is blue this means that you have different number of available rooms in channel and on your own website. This can happen if you have set a limit for Max available rooms or a threshold for when to close reservation from bookings (In BAR Management-Advanced-Availability). If you hoover on the availabilty number you will see the actual availability for External and Public. In example below there are 2 available rooms in double category, on the website we have both rooms available but in the external channels we only have 1 room available.

If there is a stop icon it means that you have set a restriction for the room (In BAR Management-Advanced-Restrictions). If you hoover on the stop icon you will see the restrictions for External and Public. In there is a CO (closed out) restriction for the external channels so even though there are 2 rooms available in intranet and on your own site there are none available in the external channels. The available restrictions are CO (closed out),  CA (closed to arrival), CD (closed to departure) and CAD (closed to arrival and departure). 

Any other restriction added is shown by the rules icon. These settings are MinStay/MaxStay (In BAR Management-Advanced-Stay length) and MinPickUp/MaxPickUp  (In BAR Management-Advanced-Pick up length ). In the example below Minimum length of stay is 2 and Minimum pick up is 2 for external channels but there are no limits for your own website.