Is it just a case of changing the width height and removing the fill as was mentioned above. Generally container means the browser window but a svg element can contain other svg elements in that case the container is the parent svg. I downloaded the SVG icons from the Noun Project and they are all 100 x 100.
As a presentation attribute it can be applied to any element but it has effect only on the following eleven elements.
Support drag and drop filefiels or folder. SVG is a language for describing 2D graphics in XML. The property defined the back drop under the filter region at the time that the element was invoked. .