So, the full meaning: A 1080p full HD copy of the 2012 Scooby-Doo holiday special, sourced directly from MAX’s web servers.
It looks like you’re referring to a specific file name: Scooby-Doo.Haunted.Holidays.2012.MAX.WEB-DL.108... — likely a shortened version of a 1080p web download of the animated film Scooby-Doo! Haunted Holidays (2012). Scooby-Doo.Haunted.Holidays.2012.MAX.WEB-DL.108...