konwert binary package in Ubuntu Focal amd64

 `konwert' is yet another charset converter. Some particular features are:
  * one-to-many conversions
  * context-dependent conversions
  * approximations of some unavailable characters
  * (as a result) ability to transcript e.g. Russian Cyrillic into Polish
 phonetic equivalent
 .
 `filterm' applies filter conversion to a terminal's I/O, to get on-the-fly
 charset conversion, and customized input methods.

Source package