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The big question with the RF mount was, if there were ever APS-C bodies coming.
Canon's stance is there are two mounts, RF (full frame) and EF-M (APS-C), the latter for small consumer oriented products. However, the EF-M line remains limited.
The new 600mm and 800mm lenses, while specialist, are really inexpensive (and light), and suited
for the enthusiast masses  (birders etc.). In theory they could go well with EF-M.
But I doubt that Canon will release them for EF-M. It looks like EF-M will remain a consumer segment with a smallish lens selection, with the usual kit zooms and a few primes.

I guess a reasonable compact RF body with high pixel density could be made, so that no APS-C specific
body is called for. However, there is the cost issue, APS-C is cheaper, and compact EF-S 10-18 and EF-S 18-55 like Kit lenses could only be made with a smaller image circle. The current 24-105 is quite light, but lacks the UWA.
Currently it doesn't look like a APS-C like body will be forthcoming. Birders have to stick the 600/800 mm lenses on a high megapixel FF body.

In the very long run though, Canon probably will have to abandon EF-M, simply because the RF communication protocol can do so much more.  So, will there ever be an RF-S line, or is that also being eaten by the smartphones. These 600 and 800 lenses are quite unexpected, and suggest the Canon is gearing the RF line now also towards lower budgets, but probably stays exclusively FF, at least for the foreseeable future?
Thoughts?

Concerning the RF lens protocol:
It is fully EF backward compatible, and has more contacts. EF-M  could have a version II, where they add more contacts (the room is there), and have a similar protocol to RF and keep EF-M version I backward compatibility.

Canon sells a lot of FF lenses compared to APS-C lenses, simply because most lens buyers have FF or FF and a smaller format. This explains the rather standard APS-C  line up.
Of course, a few who would like to use RF FF lenses on EF-M will be disappointed. 

EF-M has the big advantage over RF of much smaller bodies possible due to the smaller diameter, and small is a big seller in the mirrorless APS-C segment.