Explain. This representation is only available for records
belonging to the Explain schema.
Summary. This ASN-1 based structure is only available for records
belonging to the Summary schema - or schema which provide a mapping
to this schema (see the description of the schema mapping facility
above).
SOIF. Support for this syntax is experimental, and is currently
keyed to a private Index Data OID (1.2.840.10003.5.1000.81.2). All
abstract syntaxes can be mapped to the SOIF format, although nested
elements are represented by concatenation of the tag names at each
level.