svg:testAttrs 

Common attributes to check for system capabilities

Attribute Group Information

Attributes

QName Type Fixed Default Use Inheritable Annotation
requiredExtensions svg:ExtensionListType optional
requiredFeatures svg:FeatureListType optional
systemLanguage svg:LanguageCodesType optional

Used By

Complex Types svg:aType, svg:altGlyphType, svg:animateColorType, svg:animateMotionType, svg:animateTransformType, svg:animateType, svg:circleType, svg:clipPathType, svg:cursorType, svg:defsType, svg:ellipseType, svg:foreignObjectType, svg:gType, svg:imageType, svg:lineType, svg:maskType, svg:pathType, svg:patternType, svg:polygonType, svg:polylineType, svg:rectType, svg:setType, svg:svgType, svg:switchType, svg:textPathType, svg:textType, svg:trefType, svg:tspanType, svg:useType

Source 

<attributeGroup name="testAttrs">
  <annotation>
    <documentation>Common attributes to check for system capabilities</documentation>
  </annotation>
  <attribute name="requiredFeatures" type="svg:FeatureListType" use="optional"/>
  <attribute name="requiredExtensions" type="svg:ExtensionListType" use="optional"/>
  <attribute name="systemLanguage" type="svg:LanguageCodesType" use="optional"/>
</attributeGroup>