I just saw TRANS-579 being resolved and the IPT plugin made available. As I've stumbeled with translation (paused the translation, because it took to much effort to find the correct variable names) in the past I was eager to check it out.
As a test I continued some (Dutch, Netherlands) NL_nl translations and this worked already very nice. After having translated a few things I wanted to check if it was possible to 'upload' them to Atlassion, because it doesn't make sense in translating the same things over and over upon new releases.

In the TRANSLATION ADMINISTRATION section I used the Translations option. I would expect to find the variables I've translated, but the list was empty:

I would have expected a 'Showing translated items for Dutch (Nederland)' section.