I remain to be convinced *any* of this is going to happen.
We have Peter Wild originally suggesting that RO be open sourced, the inference being that if *his* shares were bought that somehow Castle would be "persuaded" to open source RISC OS. Point is he had *plenty* of oppertunity to make Castle see the "wisdom" of that course while *he* held the shares yet RO5 is still *closed*, so how come? Was it (i). He couldn't persuade them (ii). 25% just don't cut it ? Either being the case I don't see why changing the ownership of 25% of the voting stock and handing it to RO Open will make much difference. I asked this question before and NO ONE bothered to answer.
As to the central contention that Castle are "considering" opensourcing it - well I am considering winning the Lottery - but that doesn't mean it's going to happen . No company with any nouse would *not* consider all its options - this does not necessarily translate into any considered course being taken though.
If (and this is a conjecture) RISC OS were to be open sourced - then I'd suspect some parts would be open while others would be "binary only* (as others have suggested). Regarding the nature of the license it doesn't need to be (and probably shouldn't be) GPL. Possibly LGPL or perhaps even a license "concocted" for the RISC OS release (and this could be open enough to allow code sharing and development without damaging RO's commercial prospects (e.g., restricting use to native ARM hardware (no emulation), non-porting to other OS'es and so on - all measures to prevent any useful bits being stripped from RO by "oppertunists" who'd take without giving back to the platform).
That all being said I still think there are elements of Drobian speculation at work - and would be more comfortable hearing the outcome of Castle's consideration from the horse's mouth (as it were). In short let's all wait and see what happens.
As for ROL, I think Nelson of the Simpsons says it best "Ha, Ha...."