"[2][3] An XML processor that encounters a violation of the well-formedness rules is required to report such errors and to cease normal processing.
This policy, occasionally referred to as draconian,[4] stands in notable contrast to the behavior of programs that process HTML, which are designed to produce a reasonable result even in the presence of severe markup errors[5] in the spirit of Postel's law ("Be conservative in what you send; be liberal in what you accept").
The left and right angle bracket codes are a convention, albeit clear and distinctive, not an absolute requirement.
Well-formed documents also bring into focus the issue of valid versus correct XML.
The emphasis on well-formed documents has developed within the publishing industry where the use of left and right angle bracket delimited information has become problematic.
[citation needed] Emphasis on the well-formed document allows for the definition, delimiting, and nesting of content to be managed within programs that are not XML, per se, but exhibit the characteristics or potential for being well formed.