Is where new features go when you forget to scope and prioritize them, relying instead on the deluded fantasy that the new feature you are talking about is just "this small thing" that we'll do "now". It is easy to fall into this delusion because the meeting discussing the new feature was very genial. You can tell a feature has been stashed in that forsaken crawl space when:

1. It has no story cards or to-dos attached to it -- it's just something you're "taking care of".
2. Alternately, it has one card -- with few or no details. The title of this one card could translate without too much trouble into "Write Big New Feature". If you were questioned about that card you would grudgingly admit that it could be an umbrella for ten or twenty other cards, including things like: figure out what this feature actually does, CRUD all the resources (once it becomes clear what the resources are), and design UI.
3. Other cards or to-dos are left open and unfinished while you "take care of this quick thing". Leaving them open supports the delusion that you're only gone for a second -- to the corner store, as it were, and not fleeing to Argentina to start a new life.

Other things you might also find in that crawl space when you start poking around it are:

1. The fictional project deadline someone in your company insisted on having set in stone (that is conspicuously about half the time it will take to complete the project).
2. The unfinished tails of "completed" features, e.g., "Yeah, the widget is done! I mean, it doesn't work in Safari yet and the we're gonna change the background image from a gremlin to a frog, but essentially, it's done."
3. The chocolate bar that had no calories because you ate it standing up.