A sample of the metadata element in an OPF file.

metadata_in_opf_sample.opf

<?xml version="1.0" encoding="UTF-8"?>
<package xmlns="http://www.idpf.org/2007/opf" dir="ltr" prefix="se: http://standardebooks.org/vocab/1.0" unique-identifier="uid" version="3.0" xml:lang="en-US">
    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        <!--The DCMES elements-->
        <dc:identifier id="uid">url:https://standardebooks.org/ebooks/lewis-carroll/alices-adventures-in-wonderland</dc:identifier>
        <dc:title id="title">Alice's Adventures in Wonderland</dc:title>
        <dc:language>en-GB</dc:language>
        <dc:creator id="author">Lewis Carroll</dc:creator>
        <dc:publisher id="publisher">Standard Ebooks</dc:publisher>
        <dc:date>2015-05-12T00:01:00Z</dc:date>
        <!--The meta elements-->
        <meta content="cover.jpg" name="cover"/>
        <meta property="dcterms:modified">2017-03-09T17:21:15Z</meta>
        <!--The link elements-->
        <link href="onix.xml" rel="onix-record"/>
        <!--Other elements-->
    </metadata>
    <!--Other elements-->
</package>