Examine source code of SGDB Button on Steam

{
  "manifest_version": 3,
  "name": "SGDB Button on Steam",
  "version": "1.0.5",
  "description": "Adds a button on Steam games that brings you to their SteamGridDB entry.",
  "icons": {
    "16": "icons/icon_16.png",
    "32": "icons/icon_32.png",
    "48": "icons/icon_48.png",
    "64": "icons/icon_64.png",
    "96": "icons/icon_96.png",
    "128": "icons/icon_128.png"
  },
  "permissions": [
    "storage"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "sgdb-extension@goblincave.synology.me"
    }
  },
  "action": {
    "default_icon": "icons/icon_128.png",
    "default_popup": "popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "*://store.steampowered.com/app/*",
        "*://steamcommunity.com/app/*",
        "*://steamcommunity.com/id/*",
        "*://steamcommunity.com/profiles/*"
      ],
      "js": [
        "script.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "icons/sgdb_16.png"
      ],
      "matches": [
        "*://store.steampowered.com/*",
        "*://steamcommunity.com/*"
      ]
    }
  ]
}