tmx
What is a .tmx file?
application/x-tmx+xml
TMX (Translation Memory eXchange) is an XML standard for exchanging translation-memory segments between CAT tools. A TMX file holds translation units with aligned source and target segments plus metadata.
How to use a .tmx file
Use an example .tmx file to test translation-memory importers, TMX validators, and converters to/from XLIFF or gettext catalogs.