Terrace

It's probably a "limited common element" but you have to see exactly what the Offering Plan says.

One question I would ask is how many people can physically access it? Could the building make it accessible to all residents via some simple modifications such as buying a studio for common purposes? In some cases, the terrace can’t be deeded as it is intended to be a part of fire escape path accessed via fire stairs etc. Positive part of non deeded terrace which is only accessible via fire escape is that your percentage of common elements and hence, common charges and taxes will be higher if it were to be deeded.

If you are considering buying, I would ask for written representation from the managing agent about permitted use and restrictions of use approved by the board and have your lawyer opine on it. Perhaps some type of easement can be negotiated for a payment to condo building which will fulfill the fire code requirement and the buyer’s use.

Original condo dec calls for the terrace to be shared by all the units.
Access from a hallway (assume 2nd floor)
And Units 2A thru 2F have direct access to it from their units.
source; Article 14 page 19 of the condo declaration

This must have changed since 2006 because I cant see attaching terrace space to a floorplan without some private right to it.
It will require a conversation with the broker and managing agent

And check if the condo can take the space back if they want to do something else with it, and under what conditions -- there was a case with a building on the UES (3rd in the 70s/80s maybe?) where the building co-op board permitted the ground floor tenant to expand their a/c capacity by installing units on the building's 2nd floor setback -- reasonably adjacent to 2nd floor owners' windows.