Book 5 - The Alley
The Alley is a room. "The alley is a tight space situated between the jailhouse and the saloon. Blocked on either side, all you can really see here is a window."
The jailhouse window is a door. It is north of the Alley and south of the Jailhouse. It is scenery. The indefinite article is "the". The description is "Through the window, you can see [the other side of the jailhouse window]."
Instead of examining or searching the jailhouse window:
say "Through the window, you make out [the other side of the jailhouse window]."
Instead of climbing the jailhouse window:
try entering the jailhouse window.