10. XMQ/HTMQ – see XML and HTML in a new light - Fredrik Öhrström

XMQ is an alternative format for XML/HTML which is easier to read and write for non-markup use cases, such as data storage, configuration files and documents with layout. For these use cases the standard format for XML/HTML is not always ideal. For example there is unnecessary verbosity in using markup tags both for opening and closing tags and the whitespace
rules makes pretty printing hard and sometimes impossible.

XMQ solves these problems by using braces for the hierarchical structure and it simplifies whitespace handling by requiring all content whitespace to be quoted. Tags with simple content can be presented as key=value pairs where safe values need not be quoted at all. Quoted content has its incidental indentation removed which means that it can always be pretty printed. This makes XMQ easier to read and write and maps well to other key value based languages like JSON while maintaining full XML compatibility. XMQ can always be printed in a single line
compact form which often requires less bytes than the corresponding compact XML/HTML.