As a publisher I am able to opt out of DRM with all the majors like Amazon and Apple, but there is no indication that my book is DRM-free, nor a way to search f

As a publisher I am able to opt out of DRM with all the majors like Amazon and Apple, but there is no indication that my book is DRM-free, nor a way to search for DRM-free books on their stores. I wish there were. I can imagine a scene in the next book about that kind of stuff... "Here you go," said Count Modulo, "That is the lock, and that is the key." "So the key opens the lock?" Lauren asked. "Oh yes, but you can't open it." "Why not?" "Because it's locked, dear child. See?" [demonstrates.] "But you also gave me the key!" "Well, yes, technically you could use the key, but you mustn't do anything that silly..."