http://www.rfc-editor.org/rfc/rfc5784.txt
RFC 5784: Sieve Email Filtering: Sieves and Display Directives in XML, N. Freed, S. Vedam2010-03-01T23:00:00-00:00The XML representation also defines additional elements that have no counterparts in the regular Sieve language. These elements are intended for use by graphical user interfaces and provide facilities for labeling or grouping sections of a script so they can be displayed more conveniently. These elements are represented as specially structured comments in regular Sieve format. [STANDARDS-TRACK]