The image set is not, but subSilver is GPL.
phpBB Downloads Page wrote:
The subSilver SDK is not released under the GPL and is not subject to that licence.
Has the license changed, and the page not updated? Or is subSilver still restricted as per the Downloads page? Just looking to confirm... or am I missing something specific?
Never mind, I think I figured it out... the template files are part of the GPL, but the images referenced by the template files are not. Is that correct?