Examine source code of Passume

{
  "manifest_version": 2,
  "name": "Passume",
  "version": "2.1.0",
  "description": "Passume helps you generate strong passwords unique for each application or website. No storage anywhere!",
  "icons": {
    "16": "./assets/icons/square_icons/256.png",
    "24": "./assets/icons/square_icons/256.png",
    "32": "./assets/icons/square_icons/256.png",
    "48": "./assets/icons/square_icons/256.png",
    "64": "./assets/icons/square_icons/256.png",
    "72": "./assets/icons/square_icons/256.png",
    "96": "./assets/icons/square_icons/256.png",
    "128": "./assets/icons/square_icons/256.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "16": "./assets/icons/square_icons/256.png",
      "24": "./assets/icons/square_icons/256.png",
      "32": "./assets/icons/square_icons/256.png",
      "48": "./assets/icons/square_icons/256.png",
      "64": "./assets/icons/square_icons/256.png",
      "72": "./assets/icons/square_icons/256.png",
      "96": "./assets/icons/square_icons/256.png",
      "128": "./assets/icons/square_icons/256.png"
    },
    "default_title": "Passume",
    "default_popup": "firefox_popup/main_popup_v2.html"
  }
}