Add several comments for explaining the behaviour

src/options/options.js

@@ -27,9 +27,12 @@ async function restoreOptions() {
 	let getting = storage.sync.get("logging");
 	getting.then(setCurrentChoice, onError);
 
+	// Because we cannot use await/async, we fetch the current tab URL on startup and persist it
+	// inside a hidden <input>, just so that we can access it synchronously in the submit event.
 	const u = await getCurrentTabURL();
 	currentOriginPatternEl.value = `${u.origin}/*`; // we MUST end it with a asterisk for pattern matching
 
+	// Query the permissions for the current page. If we don't have them, ask for them.
 	const hasPermissions = await permissions.contains(getPermissionsForCurrentPage());
 	manifestPermissionForm.style.display = hasPermissions ? "none" : "block";
 }
@@ -41,6 +44,9 @@ document.querySelector("#resetbutton").addEventListener("click", async () => {
 });
 
 manifestPermissionForm.addEventListener("submit", () =>
+	// WARNING: Whatever you do, do NOT, I repeat, use await/async here.
+	// If you do that, the request of permissions is going to fail.
+	// https://bugzilla.mozilla.org/show_bug.cgi?id=1398833
 	permissions
 		.request(getPermissionsForCurrentPage())
 		.then(getCurrentTabID)