Landmark Navigation via Keyboard or Pop-up

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "minimum_chrome_version": "80",
  "icons": {
    "16": "landmarks-16.png",
    "32": "landmarks-32.png",
    "48": "landmarks-48.png",
    "128": "landmarks-128.png"
  },
  "browser_action": {
    "default_icon": {
      "16": "landmarks-16.png",
      "24": "landmarks-24.png",
      "32": "landmarks-32.png"
    },
    "default_title": "Landmarks",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "chrome_style": false,
    "page": "options.html",
    "open_in_tab": true
  },
  "permissions": [
    "<all_urls>",
    "storage",
    "webNavigation",
    "tabs"
  ],
  "manifest_version": 2,
  "name": "__MSG_extensionFullName__",
  "short_name": "__MSG_extensionShortName__",
  "version": "2.12.0",
  "description": "__MSG_extensionDescription__",
  "author": "David Todd, Matthew Tylee Atkinson",
  "homepage_url": "http://matatk.agrip.org.uk/landmarks/",
  "default_locale": "en_GB",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ]
    },
    {
      "matches": [
        "http://matatk.agrip.org.uk/landmarks/"
      ],
      "js": [
        "addHelpLinkToHomePage.js"
      ]
    }
  ],
  "commands": {
    "toggle-all-landmarks": {
      "description": "__MSG_toggleAllShortcutDescription__"
    },
    "main-landmark": {
      "suggested_key": {
        "default": "Alt+Shift+M"
      },
      "description": "__MSG_mainLandmarkShortcutDescription__"
    },
    "prev-landmark": {
      "suggested_key": {
        "default": "Alt+Shift+P"
      },
      "description": "__MSG_previousLandmarkShortcutDescription__"
    },
    "next-landmark": {
      "suggested_key": {
        "default": "Alt+Shift+N"
      },
      "description": "__MSG_nextLandmarkShortcutDescription__"
    },
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+Shift+L"
      }
    }
  },
  "devtools_page": "devtoolsRoot.html"
}