The current process of manually importing translations by means of po files is not an optimal user experience and requires many individual steps which are not self explanatory. Think you run a site with 40 modules and 3 foreign languages. You'll need to download 123 (3*40 for contrib and 3 for core) translation files and check them for updates manually.
An automated process to import and update interface translations when a site is installed, build and maintained. The functionality provided by Localization Update module is therefore required to be in Drupal core.
The below state diagram describes the processes involved in this automated process.
The following use cases should be supported:
- Install Drupal with one language other than English
- Install Drupal as part of an installation profile with one or multiple languages
- Add/remove/update modules
- Add/remove/update languages
- Update interface translations manually and automatically (cron)
- Use local po files and/or remote translation server as translation source.
- Respect existing local translations and/or translation changes when importing and updating