felipelavinz on "[Plugin: WordPress SEO by Yoast] URL Encoding on sitemaps"

Around line 553:

function sitemap_url( $url ) {
		if ( isset( $url['mod'] ) )
			$date = mysql2date( "Y-m-d\TH:i:s+00:00", $url['mod'] );
		else
			$date = date( 'c' );
		$url['loc'] = htmlspecialchars( $url['loc'] );
		$output = "\t<url>\n";