Merge pull request #21503 from nullaus/bug1035367

bug 1035367 - Update download_ui.js so that it uses data-l10n-id and dat...
(cherry picked from commit 6da21120e77b6a4ad878dd4531305cd393f6734c)
Merge pull request #21553 from nullaus/v2.0

Merge pull request #21503 from nullaus/bug1035367