Kryonoglou You can find this file here. Search for {ago} to find the lines you're looking for.
A general guide to translations here or by looking at the English extension Github (note, I linked to the 5b14897 commit, which is the last one compatible with Beta 7.1, the current dev-master has changes that will only work with the upcoming beta 8).
You can also use Flagrow Linguist to edit these lines specifically.
