This extension:   

http://hl7.org/fhir/StructureDefinition/elementdefinition-minValueSet

exists but is not documented as suggested in @fhir-26028 for the companion 

http://hl7.org/fhir/StructureDefinition/elementdefinition-maxValueSet 

Suggest adding an additional new subsection under 4.1.4 Controlling the use of Coded Values(http://hl7.org/fhir/terminologies.html#binding) to explain the use of this extension. 

Description from extension:

Status: draft. Extension maintained by: Health Level Seven, Inc. - FHIR Core WG 

The minimum allowable value set, for use when the binding strength is 'required' or 'extensible'. This value set is the minimum value set that any conformant system SHALL support.

Note: the extension is owned by FHIR-I, but vocab is addressing the maxValueSet extension. Assigning to vocab for consistency.