File: vendor/squizlabs/php_codesniffer/src/Standards/PEAR/Docs/Functions/ValidDefaultValueStandard.xml

<documentation title="Default Values in Function Declarations">
    <standard>
    <![CDATA[
    Arguments with default values go at the end of the argument list.
    ]]>
    </standard>
    <code_comparison>
        <code title="Valid: argument with default value at end of declaration">
        <![CDATA[
function connect($dsn, <em>$persistent = false</em>)
{
    ...
}
        ]]>
        </code>
        <code title="Invalid: argument with default value at start of declaration">
        <![CDATA[
function connect(<em>$persistent = false</em>, $dsn)
{
    ...
}
        ]]>
        </code>
    </code_comparison>
</documentation>