Source
File: wp-admin/includes/template.php
function find_posts_div( $found_action = '' ) {
?>
<div id="find-posts" class="find-box" style="display: none;">
<div id="find-posts-head" class="find-box-head">
<?php _e( 'Attach to existing content' ); ?>
<button type="button" id="find-posts-close"><span class="screen-reader-text"><?php _e( 'Close media attachment panel' ); ?></span></button>
</div>
<div class="find-box-inside">
<div class="find-box-search">
<?php if ( $found_action ) { ?>
<input type="hidden" name="found_action" value="<?php echo esc_attr( $found_action ); ?>" />
<?php } ?>
<input type="hidden" name="affected" id="affected" value="" />
<?php wp_nonce_field( 'find-posts', '_ajax_nonce', false ); ?>
<label class="screen-reader-text" for="find-posts-input"><?php _e( 'Search' ); ?></label>
<input type="text" id="find-posts-input" name="ps" value="" />
<span class="spinner"></span>
<input type="button" id="find-posts-search" value="<?php esc_attr_e( 'Search' ); ?>" class="button" />
<div class="clear"></div>
</div>
<div id="find-posts-response"></div>
</div>
<div class="find-box-buttons">
<?php submit_button( __( 'Select' ), 'primary alignright', 'find-posts-submit', false ); ?>
<div class="clear"></div>
</div>
</div>
<?php
}