coreattrs 

core attributes common to most elements
id       document-wide unique id
class    space separated list of classes
style    associated style info
title    advisory title/amplification

Attribute Group Information

Attributes

QName Type Fixed Default Use Inheritable Annotation
class xs:NMTOKENS optional
id xs:ID optional
style StyleSheet optional
title Text optional

Used By

Attribute Group attrs
Elements applet, bdo, br, font, iframe, isindex

Source 

<xs:attributeGroup name="coreattrs">
  <xs:annotation>
    <xs:documentation>core attributes common to most elements id document-wide unique id class space separated list of classes style associated style info title advisory title/amplification</xs:documentation>
  </xs:annotation>
  <xs:attribute name="id" type="xs:ID"/>
  <xs:attribute name="class" type="xs:NMTOKENS"/>
  <xs:attribute name="style" type="StyleSheet"/>
  <xs:attribute name="title" type="Text"/>
</xs:attributeGroup>