Originally Posted by kovidgoyal
For example, ADE refuses to handle anchors names that start with a number.
Well, according to the HTML4 spec
ID and NAME tokens must begin with a letter
([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods (".").
Maybe that's changed in XHTML, though.