When to use svg attributes

Are you inlining your svg in HTML5? Just use<svg></svg> tags without attributes.

Are you linking the SVG as an image, background-image or importing it another way that causes the User Agent to use an XML parser? Then you need the xmlns attributes like so:

<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">`