Address code review comments for experimental.md

Author: yo-h

docs/experimental.md

@@ -2,6 +2,8 @@
 
 In addition to our standard CodeQL queries and libraries, this repository may also contain queries and libraries of a more experimental nature. Experimental queries and libraries can be improved incrementally and may eventually reach a sufficient maturity to be included in our standard libraries and queries.
 
+Experimental queries and libraries may not be actively maintained as the standard libraries evolve, may be changed in backwards-incompatible ways or may be removed entirely in the future without deprecation warnings.
+
 ## Requirements
 
 1. **Directory structure**
@@ -23,7 +25,7 @@ In addition to our standard CodeQL queries and libraries, this repository may al
 
 4. **Compilation**
 
-    - Compilation of the query and any associated libraries and tests must be resilient to future development of the standard libraries. This means that the functionality cannot depend on the output of `getAQlClass` and it cannot use internal APIs.
+    - Compilation of the query and any associated libraries and tests must be resilient to future development of the standard libraries. This means that the functionality cannot use internal APIs, cannot depend on the output of `getAQlClass` and cannot make use of regexp matching on `toString`.
     - The query and any associated libraries and tests must not cause any compiler warnings to be emitted (such as use of deprecated functionality or missing `override` annotations).
 
 5. **Results**
@@ -38,5 +40,3 @@ In addition to our standard CodeQL queries and libraries, this repository may al
 
 Other criteria typically required for our standard queries and libraries are not required for experimental queries and libraries. In particular, fully disciplined query [metadata](docs/query-metadata-style-guide.md), query [help](docs/query-help-style-guide.md), tests, a low false positive rate and performance tuning are not required (but nonetheless recommended).
 
-Experimental queries and libraries may not be actively maintained as the standard libraries evolve and may be removed in the future.
-