This is used to reduce memory on 水, where {{character info}} causes the page to go over the memory limit. To use it, expand the wikitext of each instance of {{character info}} and place it on a the page Template:character info/<character> (with only one character info per subpage), and then put {{character info/subpage}} at the beginning of the entry where you would have put {{character info}}. You can pass {{character info/subpage}} a parameter like with {{character info}} to use another character, which should be used if a page has multiple character info templates with different characters. Or use {{character info/save memory}}.