Rewrite parts/

sources/sections/02-conformance.adoc

@@ -4,15 +4,17 @@
 Conformance to the ModSpec by technical implementation standards 
 can be tested by inspection. The test suite is in <<annex-A>>.
 
-There is conformance class for this document:
+There is one conformance class for this document:
 
-. Standards documents in general (the core) -- see <<cls-6>> and <<annex-A-1>>
+. The Core: Common requirements for standards documents in general. See <<cls-6>> and <<annex-A-1>>
 
 This document contains normative language and thus places requirements on
 conformance, or mechanism for adoption, of candidate standards to which the ModSpec
 applies. In particular:
 
 * <<cls-6>> specifies the core requirements which shall be met by all conformant
 standards.
-* <<cls-7>> gives information on how the ModSpec is to be applied to extensions to the core model for requirements,
+* <<cls-7>> gives information on how the ModSpec is to be applied to extensions to the core model for requirements and
 conformance clauses.
+
+Such extensions are defined in additional Parts (volumes) to the Core.