From Electrical Engineering TA Handbook
The 'Login successful' page appears when you have successfully logged in to Wikipedia. On the same page, you may also see a row of icons for other Wikimedia sites. They are to show you that you have also been automatically logged in to those sites by means of unified login. If you do not recognise an icon, you can hover the mouse pointer over it to reveal the name of the site. Clicking the icon will do nothing.
If Wikipedia was unable to log you in to one of the other sites, then the corresponding icon will not appear. It may simply be absent, or, if you are using Mozilla Firefox, text may appear in its place.
This help page is a stub. You can help by.