Examine source code of Northern Proof Reading

{
  "manifest_version": 2,
  "name": "Northern Proof Reading",
  "version": "1.0",
  "description": "A cool, measured palette inspired by proof pages and northern light. Subtle color relationships create a focused environment suited for long sessions of careful reading.",
  "theme": {
    "colors": {
      "frame": "#20272d",
      "tab_background_text": "#e1e5e8",
      "toolbar": "#2a3239",
      "toolbar_text": "#e1e5e8",
      "toolbar_field": "#eef1f3",
      "toolbar_field_text": "#20272d",
      "tab_line": "#7a8f9e"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6583ca3d-0cb4-461f-bde6-eb35769a2caf}"
    }
  }
}