This is more of a discussion opener, than a bug.
We have to start thinking about the jetpack update scenario. It basically means for us that a jetpack author will push a new version of the jetpack that we already have tracked (= same jetpackID).
Now, what we need to do here is to distinguish between versions of jetpacks and entities used by given versions. We also want to reuse as much as possible.
One particular complication here is the per-line exception as it may change the exact line number value in between versions.
fim: do you have any guess on what we could try to do here? What approach fits transifex? I'm worried that we will have to slightly modify the models and it makes sense to have a Jetpack model for now (with its versions). I'm also not sure how it'll translate onto transifex vocabulary.