i18n

for some reason, I lost my i18n file when migrating from 2.2 to 3.
but I had a backup! though it seems valid, there is no way to see my translated messages in the i18n tool while the software is using them!
Further modifications done by the i18n tool are visible, but not former ones. is the software tracking the mods done to that table, or simply loading it? what is the mechanism in between the default i18n table and the solution one when they are different? 2nd one overwrites 1st one? unless msgs are not all defined? the doc says very few things about it.

seems like someone answered, but when I click the link I received, “not found”…