<?php
 
function fontVersion($source, $filename){
  $start = strpos($source, $filename) + strlen($filename);
  $end = strpos($source, ')', $start);
  return substr($source, $start, $end - $start);
}
 
$source = "
...
src: local('Lato Light Italic'), local('Lato-LightItalic'),
        url(/fonts/lato-v16-latin-300italic.woff2?a21767e20d27a9c06007c981a8e5f827) format('woff2'),  url(/fonts/lato-v16-latin-300italic.woff?8e90b967ea69fc68b130d36cc34d41c0) format('woff'),  url(/fonts/lato-v16-latin-300italic.ttf?329d60785944501134891f948f41c001) format('truetype'),  url(/fonts/lato-v16-latin-300italic.svg?17e346950dce164549968b7b93d48f2d#Lato) format('svg'); /* Legacy iOS */
...
";
 
echo fontVersion($source, 'lato-v16-latin-300italic.woff2');
 

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