manifest.json

{
  "manifest_version": 2,
  "name": "BiB/i",
  "version": "1.0",
  "applications": {
    "gecko": {
      "id": "[email protected]"
    }
  },
  "permissions": [
    "tabs"
  ],
  "background": {
    "scripts": ["open-tab.js"],
    "persistent": false
  },
  "browser_action": {
    "default_title": "BiB/i"
  },
  "web_accessible_resources": [
    "*"
  ]
}

open-tab.js

'use strict';

chrome.browserAction.onClicked.addListener(function(aTab) {
  chrome.tabs.create({'url': 'bib/i/index.html'});
});