The CER Editor stores its rule sets on the database rather than the file system. To help identify rule sets that can be customized compliantly, please refer to the Ruleset Interdependencies developer documentation which can be found alongside the Data Dictionary. Any rule sets shipped in the core component must NOT be customized.
The HealthCareRuleSet is documented as customisable, but note that it contains two infrastructure rule classes which must not be customised. They are the AbstractObjective rule class and the DefaultObjective rule class. Similarly the HealthCareScreeningRuleSet is documented as customisable, but it contains the AbstractProgram rule class which is considered infrastructure and must not be customised. Solutions may have additional compliancy statements about their rule sets documented elsewhere.