[DaSHacka]

You're reading that diagram backwards.

NetworkManager and ConnMan can optionally _USE_ iwd as a backend _INSTEAD OF_ wpa_supplicant.

iwd does _NOT_ use NetworkManager/ConnMan

Source: gentoo user who explicitly avoids the buggy disaster that is NetworkManager+wpa_supplicant whenever possible

[cassianoleal]

I noticed my error. To be fair, I don't think I read the diagram backwards. I think the diagram is drawn backwards instead. In it, iwd seems to talk to the iwd backend via D-Bus as they're close together.

Or maybe that's a diagram technique I'm just not used to.

[yjftsjthsd-h]

It reads as a fairly normal diagram to me; NetworkManager has an iwd backend component/plugin that talks over D-Bus to iwd, which in turn stands on top of ell which in turn stands on the kernel (which itself contains a bunch of components of interest).