Rules / canonical rules

canonical.href.exists

Default
error
Plugin
canonical

The canonical link has a non-empty href.

Why: An empty canonical link points nowhere, and usually means a template left out a value.

When off: empty canonical links pass.

<!-- ✗ Fails -->
<link rel="canonical" href="" />

<!-- ✓ Passes -->
<link rel="canonical" href="https://example.com/about/" />

References