app-odoo/app_common/rng/activity_view.rng

<?xml version="1.0" encoding="UTF-8"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0"
             xmlns:a="http://relaxng.org/ns/annotation/1.0"
             datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">

    <include href="common.rng"/>

    <define name="activity">
        <element name="activity">
            <attribute name="string"/>
            <optional><attribute name="create"/></optional>
            <interleave>
                <zeroOrMore><ref name="field"/></zeroOrMore>
                <optional>
                    <element name="templates">
                        <oneOrMore>
                            <ref name="any"/>
                        </oneOrMore>
                    </element>
                </optional>
            </interleave>
        </element>
    </define>

    <start>
        <ref name="activity"/>
    </start>

</grammar>