The creator has completely disappeared and, due to the circumstances of their disappearance, will likely never return. Their SL account was banned, likely due to payment default. Their account getting banned is why it was removed from the Third Party Viewer list. The creator's disappearance also explains why it was removed from the Google Play Store, because they were not around to accept the new license agreement.
I would share the story behind their disappearance, but it's probably not my place to say.
I'm all for preserving the app files somewhere, but charging money for somebody else's app? That's not cool at all. Especially when the creator can't do anything about it.