itch.io

// this is just a sample to add colors 
(function(Scratch) {
   const blocks = [];
   const vars = {};
   const menus = {};
 class Extension {
     getInfo() {
       return {
         "id": "this_is_a_sample",
         "name": "Sample extension",
         "color1": "#insert hex color",
         "blocks": blocks,
         "menus": menus,
       }
     }
   }
The "insert hex color" is how you can make custom colors