NASA's next space-telescope is almost ready to launch but may be killed by cuts

Odd but related question if anyone knows:

Are all preprints on arXiv public?

Or is there actually a private unlisted preprint queue?

From behavior I've observed, I'm guessing maybe authors have the ability to hide papers and send private invites for select peer-review?

K2-18B: You Can Probably Smell That Planet from Here – Derek Lowe

That backdoor code is going to lurk for decades.

Not only will Musk be able to tap into it for years but foreign governments.

Wikipedia has this amazing chart of progress since 1975

https://en.wikipedia.org/wiki/Solar-cell_efficiency#/media/F...

(ignore the purple line which isn't cells)

But maybe cost reduction is a more important record even if it stalled at 20-25%