Below is a list of the warning message(s) produced when checking your document.
<svg xmlns="http://www.w3.org/2000/svg" version="1.0" viewBox="0 0 62 62">
The document located at <https://upload.wikimedia.org/wikipedia/commons/3/35/Arrow_icon.svg> was successfully checked as SVG 1.1 + URL + HTML + MathML 3.0. This means that the resource in question identified itself as "SVG 1.1 + URL + HTML + MathML 3.0" and that we successfully performed a formal validation of it. The parser implementations we used for this check are based on Compound XML and libxml2 (XML).
If you would like to create a link to this page (i.e., this validation result) to make it easier to revalidate this page in the future or to allow others to validate your page, the URI is <https://validator.w3.org/check?uri=https%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F3%2F35%2FArrow_icon.svg> (or you can just add the current page to your bookmarks or hotlist).
If you use CSS in your document, you can check it using the W3C CSS Validation Service.