by "keyring" we probably informally mean some service offered by an operating system / desktop environment to securely store credentials (passwords, keys, etc). e.g. for macOS this is "keychain access" (https://support.apple.com/en-au/guide/keychain-access/kyca10... ).

Different desktop operating systems implement various versions of this, calling it different things, with different APIs to use them. If you use a desktop app (e.g. browser, email client) in a popular operating system and it saves your user credentials somewhere, it should probably store them in the operating system's keyring service.

There is a python library named "keyring" that python applications can use to access them, in an aspirationally cross platform way https://pypi.org/project/keyring/