Did you find a bug?

Please create a new issue with description.
It would be nice if you provide more details such as GHC version, cabal-install version (or other build tool title and version).
Reproducible case will be appreciated.

Do you want to add a new or missing encoding?

Add file to repo (see .mapping or .xml files in ./Data/Encoding).
Install encoding generator via cabal install -fgenerate-encodings encoding-exe.
Run encoding generator with your newly added files.
List generated modules in encoding.cabal and commit file.
Ensure the package could be built.