text: // When the extension is installed or upgraded ...
  chrome.runtime.onInstalled.addListener(function() {
    // Replace all rules ...
    chrome.declarativeContent.onPageChanged.removeRules(undefined, function() {
      // With a new rule ...
      chrome.declarativeContent.onPageChanged.addRules([{
        // That fires when a page's URL contains a 'g' ...
        conditions: [
          new chrome.declarativeContent.PageStateMatcher({
            pageUrl: {
              urlContains: 'github.com',
            },
          }),
        ],
        // And shows the extension's page action.
        actions: [new chrome.declarativeContent.ShowPageAction()],
      }]);
    });
  });
  
  chrome.webNavigation.onHistoryStateUpdated.addListener(function(details) {
    chrome.tabs.sendMessage(details.tabId, {
      url: details.url,
    });
  });
  