None.

A Promise that will be fulfilled with an array of cookies.CookieStore objects representing all the existing cookie stores.

In the following snippet, the getAllCookieStores() method is used to retrieve all the cookie stores currently available in the browser, and print out each cookie store ID, and the tabs that currently share each cookie store.

function logStores(cookieStores) {
  for (const store of cookieStores) {
    console.log(`Cookie store: ${store.id}\n Tab IDs: ${store.tabIds}`);
  }
}

browser.cookies.getAllCookieStores().then(logStores);

Each member of the cookieStores array is a cookies.CookieStore object.