Since XLIFF is very popular and there was no XLIFF 2.0 from Pimcore before, we decided to develop it and provide it as a module.
A standard for translation management
XLIFF = XML Localization Interchange File Format
This is an XML format for the representation of hierarchically structured contents. The format is specially designed for the low-loss exchange of translation data and the associated context information. It is XML-based and therefore extensible.
The specification is aimed at the translation industry. It specifies elements and attributes to store content extracted from various original file formats and the corresponding translation.
In the meantime, XLIFF version 2.0 is available
There are several good reasons for using XLIFF2.0
Xliff 2.0 is a little more tidy than XLIFF 1.0, and makes the separation of markup and text a little easier.
The biggest advantage over XLIFF1 is that notes and annotations for the translator can be attached these can now be attached to the DataObject or document in the Pimcore backend as "notes".