MXP is a add-on file for Adobe Extension Manager tool. MXP files store extension for Adobe Creative Suite applications, for example, Photoshop or Premiere. MXP files are developed by Adobe and other vendors.

MXP file format was used up to CS5 version and was later replaced by ZXP file extension. Since Creative Cloud 2015 Adobe no longer ships Extension Manager tool with its products and add-ons must be installed directly from application’s menu.