Translations:Translation for developers/28/en

Kiwix tries to add only 100% translated languages coming from Translatewiki. So it happens often that they are more languages in the "maintenance_tools/translatewiki" directory than in the "kiwix/kiwix/chrome/locale" directory. In such a case, that simply mean the the Translatewiki language was still not integrated in Kiwix code base. We explain now how to do that.