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.
To a redirect category (rcat) template: This is a redirect from an alias/shortcut (usually), or from a redirect that is the result of a page move/rename, to a redirect category (rcat) template.
From a shortcut: This is a redirect from a shortcut in any namespace to a page in any namespace.
Shortcuts are wikilinked on community pages, talk pages, and edit summaries, but not in mainspace articles.
When appropriate, protection levels are automatically sensed, described and categorized.
