The defs element is a container element for referenced elements. For understandability and accessibility reasons, it is recommended that, whenever possible, referenced elements be defined inside of a defs.
class – string
assigns one or more css-class-names to an element
style – string
allows per-element css-style rules to be specified directly on a given element
externalResourcesRequired – bool
False: if document rendering can proceed even if external resources are unavailable else: True
transform – use