2.1.5 [W3C-EPUB3] Section 3.4.6. The DCMES Optional Elements
V0009: Leading and trailing whitespace is not trimmed
The specification states:
› 3.4.6 The DCMES Optional Elements All elements from the [DCMES] element set — except for identifier, language and title, as defined above — are designated as optional. These elements all conform to the following generalized definition: ... Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.
Leading and trailing whitespace is not trimmed.