From a camel case title: This is a redirect from a camel case page name. In the initial versions of Wikipedia, all links had to be "CamelCase", i.e., words that used medial capitals; they are "two-humped" like a Bactrian camel. These are kept as redirects to maintain edit history and to avoid breaking links that may have been made externally.
From a subpage: This is a redirect from a subpage. In a page title, a subpage name appears after a forward slash (/); for example, "Wikipedia:WikiProject Cricket/Articles", which is a subpage of "Wikipedia:WikiProject Cricket", redirects to Template:CricketRecentChanges. Not all articles or other pages with "/" in their titles are subpages (e.g. CP/M).
If this redirect is in mainspace, then it will populate the Redirects with old history category bold-linked above; if in any other namespace, then Category:Redirects from subpages will be populated.