There is no documentation about custom loaders and dumpers for the translation component. Custom loaders/dumpers can be used to support old/custom formats for translation files.

The idea would be to port what I wrote in this post: http://blog.servergrove.com/2014/03/18/symfony2-components-overview-translation/ ("custom loaders" part). If you think it can be useful, I can do it in the next DX hackday.