#data
<video xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo"/>
</video>
#errors
/video;no significant content;s
/video/source;attribute missing;src;m
/video/source/@srcset;unknown attribute;u
/video/source/@srcset;attribute not allowed:picture source;m

#data
<audio xmlns="http://www.w3.org/1999/xhtml">
  <source srcset="foo"/>
</audio>
#errors
/audio;no significant content;s
/audio/source;attribute missing;src;m
/audio/source/@srcset;unknown attribute;u
/audio/source/@srcset;attribute not allowed:picture source;m