The ID of the tab
that this instance of the devtools is attached to, represented as a number.
This can be sent to the extension's background page, so that background page can use the tabs
API to interact with the tab:
// devtools-panel.js const scriptToAttach = "document.body.innerHTML = 'Hi from the devtools';"; attachContentScriptButton.addEventListener("click", () => { browser.runtime.sendMessage({ tabId: browser.devtools.inspectedWindow.tabId, script: scriptToAttach }); });
// background.js function handleMessage(request, sender, sendResponse) { browser.tabs.executeScript(request.tabId, { code: request.script }); } browser.runtime.onMessage.addListener(handleMessage);