Forum discussion at Twitter.
Google Removes @ID from Site Name Markup
So if you have those in your code for site name markup, you can remove it.
Google wrote that today, August 2nd they have “removed unneeded mention of “@id” in the site names documentation.”
Here is what was removed, these three @id lines in the sample code on this page:
Google has removed the @id mentions in the site name documentation calling the use of @id “unneeded.” If you compare the old version of the page to the new version, you will see the example code that shows @id lines were removed.