A new feature has been just added to AMOS portal. At the translator page, when you click at +- sign, you can see a timeline of the given string. At the left side of the report, changes in the English pack are listed. At the right side, you can see changes in your language. Every record displays the origin of the change (the date, author and commit message) followed by the string value after the change.
This new feature is mostly useful for outdated strings so you can check how the string was updated in the English language pack since it was last translated.