7.19. Element title
Specifies the “rich” title of a book division (part, chapter, section, etc).
Content model
Element title can contain text and the same XHTML5
  child elements as an html:p element (that is,phrasing
  content: html:b, html:img, etc) in any order and in any
  number.
Attributes
| Name | Data type | Default value | 
|---|---|---|
| xml:base | anyURI | |
| xml:id | ID | |
| xml:lang | languageor "" (the empty string) | . | 
Other attributes: XHTML5 global attributes, including any attribute having
  a name starting with "data-".
Parents
The
  following elements contain title: head.
Children
The
  following elements occur in title: the same XHTML5 child
  elements as an html:p element.
Example
| 1 2 3 4 5 | <appendix href="ssh_key.html"> <head> <title>Generating Your <html:b>SSH</html:b> Public Key</title> </head> </appendix> |