Comment 6 for bug 830584

> The way that Ubuntu deltas are indicated is very Ubuntu-specific, I don't know of a way of handling this in a generic fashion.

A reasonable algorithm may be:
If the latest version number in the destination is not present in the source's history and this version number with "build\d+$" removed is, then there's a delta that should be checked.

> Will the intermediate change log entries contain all the bugs you need to close?

Not all of them, but if a Debian uploader wanted to close an Ubuntu bug with an upload, it should happen :)