The Atom Syndication Format is an XML language used for web feeds.

These kinds of editors are generally more useful for XML languages for data rather than for storing documents.

It is often used in the specifications of XML languages, for its convenience in describing constraints on constructs those languages allow.

Biml has a syntax that's common to all XML languages.

Most XML languages are based on a single XML namespace.

Many XML languages allow the use of arbitrary elements from other namespaces.

Adso also supports a specially-defined XML language which customizes software output.

It has an XML language optimized for clearer definition of what each task does and on what it depends.

And both of them are, or can be, defined in an XML language.

Mallard is an XML language.