From a page move: This is a redirect from a page that has been moved (renamed). This page was kept as a redirect to avoid breaking links, both internal and external, that may have been made to the old page name.
From other capitalisation: This is a redirect from a title with another method of capitalisation. It leads to the title in accordance with the Wikipedia naming conventions for capitalisation, or it leads to a title that is associated in some way with the conventional capitalisation of this redirect title. This may help writing, searching and international language issues.
If this redirect is an incorrect capitalization (a typo), then it is made available to aid searches, so pages that use this link should be updated to link directly to the target.