Yes, a 3.5.0 CARES Required Element schematron is available on this site.

CARES required elements are validated by rules in the CARES 3.5.0 Required Elements schematron, which is publicly available on vendors.mycares.net. This schematron can be utilized in several ways:

• Used as-is for validation purposes in vendor and repository systems
• Used by vendors/states to build their own ePCR validation rules
• Adopted by states, with or without modifications as needed for their specific requirements

For state integration, it is required that systems adopt schematron rules that meet or exceed the severity levels defined in the CARES Required Elements schematron.

The current 3.5.0 CARES Required Element schematron rules are explained in detail here:

CARES 3.5.0 Required Elements Schematron Rules