The value must conform to BCP 47. If the value is a private use code (i.e., starts
with x- or contains -x-) it should, and if not it may, match the
value of an ident attribute of a language element supplied in the TEI
Header of the current document.
rend
(rendition) indicates how the element in question was rendered or presented in the source text.
any string of characters; if the typographic rendition of a text is to be
systematically recorded, a systematic set of values for the rend attribute should
be defined.
<head rend="align(center) case(allcaps)"> <lb/>To The <lb/>Duchesse <lb/>of <lb/>Newcastle, <lb/>On Her <lb/> <hi rend="case(mixed)">New Blazing-World</hi>. </head>
rendition
points to a description of the rendering or presentation used for this element in the
source text.