Examine source code of Reader Comfort

{
  "manifest_version": 3,
  "name": "Reader Comfort",
  "version": "1.8.0",
  "description": "Page tint, text size/spacing, accessible fonts, a reading ruler, highlighter, annotations, and sticky notes for any website.",
  "browser_specific_settings": {
    "gecko": {
      "id": "reader-comfort@breadtoasting.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": [
          "websiteContent"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  },
  "permissions": [
    "storage",
    "activeTab",
    "clipboardWrite",
    "scripting"
  ],
  "host_permissions": [
    "<all_urls>",
    "https://api.dictionaryapi.dev/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icons/icon16.png",
    "32": "icons/icon32.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Reader Comfort",
    "default_icon": {
      "16": "icons/icon16.png",
      "32": "icons/icon32.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "css": [
        "reader.css"
      ],
      "js": [
        "content.js",
        "highlighter.js",
        "annotate.js",
        "notes.js"
      ],
      "run_at": "document_start",
      "all_frames": false
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "fonts/*.woff2",
        "pdf/viewer.html"
      ],
      "matches": [
        "<all_urls>",
        "file:///*"
      ]
    }
  ],
  "commands": {
    "toggle-ruler": {
      "suggested_key": {
        "default": "Alt+R"
      },
      "description": "Toggle the reading ruler"
    },
    "toggle-enabled": {
      "description": "Toggle Reader Comfort on this page (bind a key in the browser's shortcuts page)"
    },
    "toggle-highlight-quick": {
      "suggested_key": {
        "default": "Alt+H"
      },
      "description": "Toggle quick-highlight mode (highlight on select)"
    },
    "toggle-draw-mode": {
      "suggested_key": {
        "default": "Alt+D"
      },
      "description": "Toggle freehand-draw mode"
    },
    "add-note": {
      "suggested_key": {
        "default": "Alt+N"
      },
      "description": "Add a sticky note"
    }
  }
}