.xaml files are used by Microsoft Visual Studio, C# to create GUI widget layouts. It can use the same output format as .xml files.

See also: https://en.wikipedia.org/wiki/Extensible_Application_Markup_Language

I am currently using:

bat -l xml MainWindow.xaml

It would be nice if the -l xml was implied for .xaml files. If you this is acceptable, I can submit a PR.

Thanks.