In a web browser an access key or accesskey allows a computer user to immediately jump to a specific part of a web page via the keyboard.
To be able to use these access keys you need to use modifiers which can differ from browser to browser. A short list of browsers and the respective modifiers can be found here.

Available access keys in T4
access key	page which opens with the access key
1	dorf1.php
2	dorf2.php
3	karte.php
4	statistiken.php
5	berichte.php
6	messages.php
9	dorf3.php
b	back (goes to the previous village in the village list)
n	next (goes to the next village in the village list)