T-underscore

In titles, spaces and underscores are all treated the same, whether URL encoded or not. All these titles result in the same title:
 * "T "
 * T_
 * T%20
 * T%5F

In the above examples, the space is trimmed at the end of the title, resulting in the page title "T".

The encodings can be used in URL parameters to preserve the space/underline characters.