edge_fullscreen/Extension/js/background.js

function onError(error) {
  console.log(`Error: ${error}`);
}

browser.windows.getAll().then((windowInfoArray) => {
    for (currentWindow of windowInfoArray) {
        browser.windows.update(currentWindow.id, {state: "fullscreen"});
    }
}, onError);

console.log("错误！！！！");