Examine source code of FCopyrights

{
  "manifest_version": 2,
  "name": "FCopyrights",
  "version": "2.5",
  "description": "Store copyright info of stock photos as text file with only two clicks.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "permissions": [
    "tabs",
    "contextMenus",
    "downloads"
  ],
  "background": {
    "scripts": [
      "fcopyrights.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://stock.adobe.com/*",
        "https://pixabay.com/*",
        "https://unsplash.com/*",
        "https://www.pexels.com/*"
      ],
      "js": [
        "content-script.js"
      ]
    }
  ],
  "page_action": {
    "browser_style": true,
    "default_icon": "icons/icon.svg",
    "default_title": "Get Copyright Info",
    "show_matches": [
      "https://stock.adobe.com/*/images/*",
      "https://stock.adobe.com/*/video/*",
      "https://stock.adobe.com/*/templates/*",
      "https://stock.adobe.com/*/3d-assets/*",
      "https://pixabay.com/*photos/*",
      "https://pixabay.com/*illustrations/*",
      "https://pixabay.com/*vectors/*",
      "https://pixabay.com/*videos/*",
      "https://pixabay.com/*music/*",
      "https://pixabay.com/*sound-effects/*",
      "https://pixabay.com/*gifs/*",
      "https://unsplash.com/photos/*",
      "https://unsplash.com/de/fotos/*",
      "https://unsplash.com/es/fotos/*",
      "https://unsplash.com/fr/photos/*",
      "https://unsplash.com/it/foto/*",
      "https://unsplash.com/ja/%E5%86%99%E7%9C%9F/*",
      "https://unsplash.com/ko/%EC%82%AC%EC%A7%84/*",
      "https://unsplash.com/pt-br/fotografias/*",
      "https://www.pexels.com/photo/*",
      "https://www.pexels.com/video/*",
      "https://www.pexels.com/pt-br/foto/*",
      "https://www.pexels.com/pt-br/video/*",
      "https://www.pexels.com/es-es/foto/*",
      "https://www.pexels.com/es-es/video/*",
      "https://www.pexels.com/ca-es/foto/*",
      "https://www.pexels.com/ca-es/video/*",
      "https://www.pexels.com/de-de/foto/*",
      "https://www.pexels.com/de-de/video/*",
      "https://www.pexels.com/it-it/foto/*",
      "https://www.pexels.com/it-it/video/*",
      "https://www.pexels.com/fr-fr/photo/*",
      "https://www.pexels.com/fr-fr/video/*",
      "https://www.pexels.com/sv-se/foto/*",
      "https://www.pexels.com/sv-se/video/*",
      "https://www.pexels.com/id-id/foto/*",
      "https://www.pexels.com/id-id/video/*",
      "https://www.pexels.com/pl-pl/zdjecie/*",
      "https://www.pexels.com/pl-pl/video/*",
      "https://www.pexels.com/ja-jp/photo/*",
      "https://www.pexels.com/ja-jp/video/*",
      "https://www.pexels.com/zh-tw/photo/*",
      "https://www.pexels.com/zh-tw/video/*",
      "https://www.pexels.com/zh-cn/photo/*",
      "https://www.pexels.com/zh-cn/video/*",
      "https://www.pexels.com/ko-kr/photo/*",
      "https://www.pexels.com/ko-kr/video/*",
      "https://www.pexels.com/th-th/photo/*",
      "https://www.pexels.com/th-th/video/*",
      "https://www.pexels.com/nl-nl/foto/*",
      "https://www.pexels.com/nl-nl/video/*",
      "https://www.pexels.com/hu-hu/foto/*",
      "https://www.pexels.com/hu-hu/video/*",
      "https://www.pexels.com/vi-vn/anh/*",
      "https://www.pexels.com/vi-vn/video/*",
      "https://www.pexels.com/cs-cz/foto/*",
      "https://www.pexels.com/cs-cz/video/*",
      "https://www.pexels.com/da-dk/foto/*",
      "https://www.pexels.com/da-dk/video/*",
      "https://www.pexels.com/fi-fi/kuva/*",
      "https://www.pexels.com/fi-fi/video/*",
      "https://www.pexels.com/uk-ua/photo/*",
      "https://www.pexels.com/uk-ua/video/*",
      "https://www.pexels.com/el-gr/photo/*",
      "https://www.pexels.com/el-gr/video/*",
      "https://www.pexels.com/ro-ro/fotografie/*",
      "https://www.pexels.com/ro-ro/video/*",
      "https://www.pexels.com/nb-no/bilde/*",
      "https://www.pexels.com/nb-no/video/*",
      "https://www.pexels.com/sk-sk/photo/*",
      "https://www.pexels.com/sk-sk/video/*",
      "https://www.pexels.com/tr-tr/fotograf/*",
      "https://www.pexels.com/tr-tr/video/*",
      "https://www.pexels.com/ru-ru/photo/*",
      "https://www.pexels.com/ru-ru/video/*"
    ],
    "hide_matches": [
      "https://pixabay.com/*videos/search/*",
      "https://pixabay.com/*music/search/*",
      "https://pixabay.com/*sound-effects/search/*",
      "https://pixabay.com/*gifs/search/*"
    ]
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "@fcopyrights"
    }
  }
}