Be more specific about QA documentation

TESTING_AND_QA.md

@@ -7,20 +7,29 @@ deployments](DEPLOYMENT.md).
 * **Each product has a canonical checklist of tests.**
 
   The checklist includes common actions and workflows, and known past
-  regressions (things that went wrong in a past deployments).  It may
-  be divided across a few places, as follows:
-
-  The upstream repository's automated test suite is the best place for
-  a test, and is the first place we should try to put any new test we
-  write.  Most projects welcome more tests -- coverage is always
-  lagging -- so usually they're eager to have us add new tests.
-
-  In the rare cases when there are tests that are specific to an OTS
-  client and that don't belong in upstream's repository, they live in
-  our copy (our "vendor branch") of the project.  We make sure to run
-  them in addition to the upstream test set.  That is, *our* total
-  checklist is all the upstream tests plus any OTS-specific tests we
-  maintain.
+  regressions (things that went wrong in a past deployments).  
+
+  For OTS-originated projects, the starting point for the checklist is
+  a Markdown file named `TESTING_AND_QA.md` at the top-level of the
+  main product repository.  For projects where the project tree
+  structure is inherited from upstream, then the starting point is
+  whatever the convention is for that upstream.
+
+  In general, the upstream repository's automated test suite is the
+  best place for a test to live, and is the first place we should try
+  to put any new test we write.  Most projects welcome more tests --
+  coverage is always lagging -- so usually they're eager to have us
+  add new tests.
+
+  In cases when there are tests that are specific to an OTS client and
+  that don't belong in upstream's repository, they live in our copy
+  (our "vendor branch") of the project, where they are documented
+  starting from a file named `TESTING_AND_QA.md` as per above.  We
+  make sure to run those OTS-specific tests in addition to the
+  upstream test set, any time we do a QA run.
+
+  Thus, *our* total checklist is all the upstream tests plus any
+  OTS-specific tests we maintain.
 
 * **Tests that aren't automated (or aren't automated yet) we perform manually.**