jQuery is the root source of the code being picked up by the Googlebot. Within the jQuery file itself is this line...
<a href='/a' style='color:red;float:left;opacity:.55;'>a</a>
As per Google (see below), add a 301 redirect to the htaccess
file to kill this problem for good.
Redirect 301 /a http://www.mySite.com
The following is a response from Google employee JohnMu on this issue in the thread I started at Google Groups.
JohnMu
Google Employee
4:39 AM
Hi guys
Just a short note on this -- yes, we
are picking up the "/a" link for many
sites from jQuery JavaScript. However,
that generally isn't a problem, if we
see "/a" as being a 404, then that's
fine for us. As with other 404-URLs,
we'll list it as a crawl error in
Webmaster Tools, but again, that's not
going to be a problem for crawling,
indexing, or ranking. If you want to
make sure that it doesn't trigger a
crawl error in Webmaster Tools, then I
would recommend just 301 redirecting
that URL to your homepage (disallowing
the URL will also bring it up as a
crawl error - it will be listed as a
URL disallowed by robots.txt).
I would also recommend not explicitly
disallowing crawling of the jQuery
file. While we generally wouldn't
index it on its own, we may need to
access it to generate good Instant
Previews for your site.
So to sum it up: If you're seeing "/a"
in the crawl errors in Webmaster
Tools, you can just leave it like
that, it won't cause any problems. If
you want to have it removed there, you
can do a 301 redirect to your
homepage.
Cheers
John
See this SO answer for even more information:
https://stackoverflow.com/a/6587142/594235