Unexplained GET of /flutter_service_worker.js

[vsajip]

I've a basic Django setup with allauth and allauth.account in INSTALLED_APPS and the middleware enabled, and when I go to my site's home page, I get this:

Django version 5.0.10, using settings 'project.settings'
Starting ASGI/Daphne version 4.1.0 development server at http://127.0.0.1:8000/
Quit the server with CONTROL-C.
HTTP GET / 200 [0.35, 127.0.0.1:52158]
Not Found: /flutter_service_worker.js
--- Logging error ---
Traceback (most recent call last):
  File "/usr/lib/python3.10/logging/handlers.py", line 677, in emit
    s = self.makePickle(record)
  File "/usr/lib/python3.10/logging/handlers.py", line 649, in makePickle
    s = pickle.dumps(d, 1)
  File "/home/vinay/.local/share/virtualenvs/django-base/lib/python3.10/site-packages/django/urls/resolvers.py", line 105, in __reduce_ex__
    raise PicklingError(f"Cannot pickle {self.__class__.__qualname__}.")
_pickle.PicklingError: Cannot pickle ResolverMatch.
Call stack:
  File "/usr/lib/python3.10/threading.py", line 973, in _bootstrap
    self._bootstrap_inner()
  File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.10/threading.py", line 953, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python3.10/concurrent/futures/thread.py", line 83, in _worker
    work_item.run()
  File "/usr/lib/python3.10/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/home/vinay/.local/share/virtualenvs/django-base/lib/python3.10/site-packages/asgiref/sync.py", line 522, in thread_handler
    return func(*args, **kwargs)
  File "/home/vinay/.local/share/virtualenvs/django-base/lib/python3.10/site-packages/django/utils/log.py", line 241, in log_response
    getattr(logger, level)(
Message: '%s: %s'
Arguments: ('Not Found', '/flutter_service_worker.js')
HTTP GET /flutter_service_worker.js?v=1069475833 404 [0.17, 127.0.0.1:52158]

If I comment out allauth and allauth.account and the middleware, the GET to /flutter_service_worker.js disappears. Grepping the site-packages/allauth found no reference to flutter anywhere - can anyone explain where this GET is coming from? I'm using django-allauth==65.3.1.