svg.global_attributes.marker-* - attributes aren't applicable to non-markable elements

MDN URL

https://developer.mozilla.org/en-US/docs/Web/SVG/Reference/Attribute/marker-start

What specific section or headline is this issue about?

You can use this attribute with the following SVG elements:

What information was incorrect, unhelpful, or incomplete?

• <circle>
• <ellipse>
• <line>
• <path>
• <polygon>
• <polyline>
• <rect>

What did you expect to see?

• <line>
• <path>
• <polygon>
• <polyline>

Do you have any supporting links, references, or citations?

https://www.w3.org/TR/svg-markers/#intro -- introduction defines markable elements.

https://developer.mozilla.org/en-US/docs/Web/SVG/Reference/Element/marker - correct MDN documentation, I missed the applicable shapes on skim.

Do you have anything more you want to share?

This is true for the marker-mid and marker-end attributes' documentation as well. I am not a reliable source for what is correct SVG specification.

I was testing some of the examples here with a <circle> and <rect> element in the MDN playground out of curiosity of how it would choose the vertices for the markers. I got confused as to why no markers were being drawn, and I dove into the linked W3 spec to understand deeper.

If these were included purposefully, I personally would have appreciated something that indicated this attribute is a no-op for built-in shapes. For instance, the browser compatibility matrix indicating that support for these do not exist.

I greatly appreciate the MDN docs for its clear communication of web standards in addition to providing link to W3 specification and browser compatibility, and playground. This is the first time I noticed an issue in at least a decade of referencing it!

MDN metadata

Start with the referenced marker-start data and the MDN content page at files/en-us/web/svg/reference/attribute/marker-start/index.md. Compare the marker-start, marker-mid, and marker-end records against the linked SVG Markers specification and marker element documentation. Done means the compatibility data no longer lists non-markable shapes, with the same correction applied consistently to all three attributes.