Each language version of is_email() now has its own trunk.
Look in /svn/PHP/trunk for the PHP version, for example.
If you plan to make changes, use this command to check out the code as yourself using HTTPS:
svn checkout https://isemail.googlecode.com/svn/PHP/trunk/ isemail --username your.username
When prompted, enter your generated googlecode.com password. Use this command to anonymously check out the latest project source code:
svn checkout http://isemail.googlecode.com/svn/PHP/trunk/ isemail-read-only