Shopify modify assset json

shopify_modify_asset_json

{
   "asset":{
      "key":"templates\/404.liquid",
      "value":"<div id=\"col-main\" class=\"content\">\n  <h1 class=\"heading\">Page not found <span class=\"not_found\">404<\/span><\/h1>\n  <p>Perhaps you want to return to the <a href=\"\/\">home page<\/a> or <a href=\"\/search\">try a search<\/a>.<\/p>\n<\/div>\n\n<!-- BULK REDIRECT CODE: START -->\n<script type=\"text\/javascript\">\nfunction makeDoubleDelegate(a,b){return function(){if(a)a();if(b)b()}}window.onload=makeDoubleDelegate(window.onload,function(){window.onload=function(){var a=document.createElement(\"img\");var b=\"https:\"==document.location.protocol?\"https:\/\/\":\"http:\/\/\";a.src=b+\"www.aleksandrmedia.com\/tracker?r=\"+encodeURIComponent(document.referrer)+\"&c=N!8\";((document.getElementsByTagName(\"head\")||[null])[0]||document.getElementsByTagName(\"script\")[0].parentNode).appendChild(a)}()})\n<\/script>\n<!-- BULK REDIRECT CODE: END -->\n\n"
   }
}