It is strange. The WiX documentation describes it as:
As for XML manipulations, you can avoid dealing with complicated namespaces if you just use Six# extensions:
Languages String The list of language IDs (LCIDs) supported in the package.As for XML manipulations, you can avoid dealing with complicated namespaces if you just use Six# extensions:
project.WixSourceGenerated += doc => doc.Root.Select("Product/Package") .SetAttribute("Languages", 1049);