I can't speak for Linux, but it's now part of their iCloud for Windows suite with browser access via extension[1]. Exporting from Bitwarden to Passwords (on an iPhone at least) is (as of this post) a simple Export Vault operation, but non-passwords/passkeys are not supported.

1: https://support.apple.com/guide/icloud-windows/set-up-icloud...

That's correct; I only use MacOS and iOS.