Originally Posted by
mozilla
The airline includes terminal information when it timetables a flight in the GDS (see screenshot below), which could be up to 337 days in advance. Of course, subject to change.
Subject to change, and also of limited utility. For your ORD example, "Terminal 1" can be concourse B or C, but it's easily a 10+ minute walk from the end of the B concourse to the end of the C concourse.