Dmitry Bogdanov

for WP SEO by Yoast 2.0.1
wordpress-seo/inc/class-wpseo-replace-vars.php
if ( ! empty( $this->args->ID ) ) {
if ( $this->args->post_excerpt !== ” ) {
$replacement = strip_tags( $this->args->post_excerpt );
}
elseif ( $this->args->post_content !== ” ) {
$replacement = wp_html_excerpt( strip_shortcodes( $this->args->post_content ), 155 );
}
}