`label` must have content

Rule ID	Control 7
Definition	Every `label` and `legend` element must contain text content.
Purpose	A `label` or `legend` elements is only useful for accessibility when it contains content that describes the purpose of the associated form control(s).
Mappings	HTML4 Legacy Techniques (Required) HTML5 and ARIA Techniques (Required)
WCAG Success Criteria	3.3.2 Labels or Instructions (Level A, Primary Success Criterion) Other Related Success Criterion: 1.3.1 Info and Relationships (Level A) 2.4.6 Headings and Labels (Level AA)
Rule Category	Forms
Scope	Element
Target Resources	`label` and `legend` elements `label` `legend`
Techniques	Add text content to `label` and `legend` elements that describes the purpose of the form control or group of form controls.
Informational Links	HTML 4.01 Specification: The `label` element `for` attribute W3C WAI Accessibility Tutorials: Forms Concepts H44: Using `label` elements to associate text labels with form controls H88: Using HTML according to spec

label must have content