Alternatively if one wanted to get more sophisticated than just importing every version from snapshot in version number order, one might write something to look inside the package at the changelogs to try to discern the branch structure.
https://github.com/plugwash/autoforwardportergit/blob/master/pooltogit will take dscs in a pool structure and import them into git repos (one per source package) using dgit, building the history based on the changelogs. It can even follow history across source package renames.
It also has the ability to use snapshotsecure to download parent versions from snapshot.debian.org , As the code stands it only uses that functionality to request immediate parents of local versions, but it could be easily modified to grab the entire history of the package (as defined by it's changelog).
