What is WFP 4's internal file format?

Forum: Wordfast support
Topic: What is WFP 4's internal file format?
Poster: 2nl

I was working on this article: [url removed] and was wondering to which category WFP 4 belongs:

CAT tools that use XLIFF as an internal file format for translation projects

or

CAT tools that can export translation projects as XLIFF files

Thanks!

Hans