This specification reserves a number of [=properties=] to serve as possible

extension points. While some implementers signaled interest in these properties,

their inclusion in this specification was considered to be premature. Some of

these extension points were originally defined in previous versions of this

specification, while others were not. It is important to note that none of these

properties are defined by this specification. Consequently, implementers are

cautioned that use of these properties is considered experimental.

their inclusion in this specification was considered to be premature. It is

important to note that none of these properties are defined by this

specification. Consequently, implementers are cautioned that use of these

properties is considered experimental.

Implementers MAY use these properties, but SHOULD expect them and/or