Mentioned in a hatnote: This is a redirect from a title that is mentioned in a hatnote at the redirect target. The mention is usually atop the target article. It may, however, be directly under a section header, or in another article's hatnote (whenever the hatnote is under a section, {{R to section}} should also be used).
The titles of redirects mentioned in hatnotes may refer to a subject other than that of the target page. It is possible that this redirect may need to be retargeted, or become an article under its own title (see {{R with possibilities}}). If the title is a good candidate for a Wiktionary link, it may also be added.
From a cross-project redirect: This is a redirect from a title associated with an item on Wikidata. The Wikidata item associated with this page is senator (Q15686806).