Define "backwards incompatibility"

Author: brettcannon

pep-0387.txt

@@ -27,6 +27,13 @@ millions of applications and libraries. This is fantastic. However, it
 means the development team must be very careful not to break this
 existing 3rd party code with new releases.
 
+This PEP takes the perspective that "backwards incompatibility" means
+preexisting code ceases to comparatively function after a change. It is
+acknowledged that this is not a concrete definition, but the expectation
+is people in general understand what is meant by
+"backwards incompatibility", and if they are unsure they may ask the
+Python development team and/or steering council for guidance.
+
 
 Backwards Compatibility Rules
 =============================