@YGYL Do you mean you manually edited some plugins to include additional language files?

If so, this "plugin manager" could also implement support for user made translations, at the condition that the managed plugins load the strings the "standard way", i.e. using .properties files with language specific suffix. The manager could implement a text merge tool to help the user identify only the strings that have been added or changed from the previous version, and let him manually translate them, doing automatic packaging and installing. Rollback/backup support could also be implemented.

Could this meet your needs?