Examine source code of Image Forward

{
  "applications": {
    "gecko": {
      "id": "imageforward@sblask",
      "strict_min_version": "55.0"
    }
  },
  "author": "Sebastian Blask",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "browser_style": false,
    "default_icon": "icon.svg",
    "default_popup": "options/options.html",
    "default_title": "Image Forward"
  },
  "commands": {
    "abort-cycling": {
      "description": "Abort cycling through images and go back to page of origin",
      "suggested_key": {
        "default": "Ctrl+Shift+B",
        "windows": "Ctrl+Shift+X"
      }
    },
    "cycle-through-embedded-images": {
      "description": "Show first/next image embedded in page",
      "suggested_key": {
        "default": "Ctrl+Shift+Space",
        "mac": "Alt+Shift+Space"
      }
    },
    "cycle-through-linked-images": {
      "description": "Show first/next image linked from page",
      "suggested_key": {
        "default": "Ctrl+Space",
        "mac": "Alt+Space"
      }
    }
  },
  "description": "Easily cycle through images on a page or images linked from a page. Inspired by parts of Opera 12's Fast Forward.",
  "homepage_url": "https://github.com/sblask/webextension-image-forward",
  "icons": {
    "48": "icon.svg"
  },
  "manifest_version": 2,
  "name": "Image Forward",
  "options_ui": {
    "page": "options/options.html"
  },
  "permissions": [
    "<all_urls>",
    "activeTab",
    "storage",
    "webNavigation",
    "webRequest",
    "webRequestBlocking"
  ],
  "version": "2.0.7resigned1"
}