Challenges do NOT require any bruteforcing/directory fuzzing/massive amounts of traffic unless clearly specified in the challenge information below.
This is a convenient extension, storing the logins you use on various webpages and offering them to you on next visit so that you don't have to retype. It also doubles as a flag storage, websites cannot possibly get the flag out. Don't believe me? See for yourself!
Note on trying out the browser extension: Unpack the linked ZIP file to a directory. To load this directory as an extension:
In Chrome: Go to chrome://extensions/, enable Developer mode, click "Load unpacked" and select the directory.
In Firefox: Go to about:debugging, click "Load Temporary Add-on" and select any file in the directory.