Examine source code of coloured blocks

{
  "theme": {
    "images": {
      "theme_frame": "firefox1.png"
    },
    "colors": {
      "frame": "rgba(229,230,232,1)",
      "tab_background_text": "#000000"
    }
  },
  "version": "2.0",
  "name": "coloured blocks",
  "manifest_version": 2,
  "description": "I really love colours and coloured blocks like this, only slightly bigger, have been my wallpaper for a while now, but I also wanted to use it on Firefox.\nI discovered however that it gets a bit annoying to read the text because the blocks are so bright, so I made a new Persona called coloured blocks 2. The same, but a bit lighter. Now I only have to wait until it's up :)"
}