Part of lp.translations.scripts
| Class | ReplacerMixin | Replaces language and variant on all contained objects. |
| Class | TranslationMessageVariantReplacer | Replaces language on all `TranslationMessage`s with variants. |
| Class | POFileVariantReplacer | Replaces language on all `TranslationMessage`s with variants. |
| Class | MigrateVariantsProcess | Mark all POFile translation credits as translated. |