I wrote:
(...) An attribute description is an attribute type optionally followed by ;options, which are an extension of the original concept of ;language tags. A type with a language tag or user-defined ;option is a sub-type of the original type, just like "cn" is a subtype of "name".
That was a bit inaccurate. ;options like binary already existed, and they need not be subtypes IIRC. OpenLDAP's user-defined options are "tagging options", and that's the type of options which create sub-types. I'll dig up the RFCs for this, later. -- Hallvard