Rule: `fieldset` must have one `legend`

Rule ID	Control 8
Conformance	Required
Definition	Every `fieldset` element must contain exactly one `legend` element.
Purpose	Multiple `legend` elements contained in the same `fieldset` may result in the improper calculation of labels for assistive technologies.
Conformance	Required
WCAG Success Criteria	Success Criterion 3.3.2 Labels or Instructions Other Related Success Criterion: Success Criterion 1.3.1 Info and Relationships Success Criterion 2.4.6 Headings and Labels Success Criterion 4.1.1 Parsing
Rule Category	Forms
Rule Scope	Element
Techniques	A `fieldset` element should have one and only one `legend` element to describe the purpose of the form controls it contains.
Information Links	HTML Specification: The @fieldset@ element HTML Specification: The @legend@ element MDN : The Field Set Legend element W3C WAI Accessibility Tutorials: Forms Concepts H71: Providing a description for groups of form controls using fieldset and legend elements H88: Using HTML according to spec

Rule: fieldset must have one legend