FacetWP - layout builder - add MP3 URL into an HTML5 audio player

functions.php

<?php

// Add to your (child) theme's functions.php
// Change "audio-mp3" to your layout builder's item name (which defaults to "el-XXXXX")

add_filter( 'facetwp_builder_item_value', function( $value, $item ) {
    if ( 'audio-mp3' == $item['settings']['name'] && ! empty( $value ) ) {
		ob_start();
?>
 <audio controls>
  <source src="<?php echo $value; ?>" type="audio/mpeg">
  Your browser does not support the audio element.
</audio> 
<?php
		$value = ob_get_clean();
    }
    return $value;
}, 10, 2 );