Here is my favorite roundup on the subject: https://project-evidence.github.io/ https://project-evidence.github.io/ In my own amateur opinion, either natural c

Here is my favorite roundup on the subject: https://project-evidence.github.io/ https://project-evidence.github.io/ In my own amateur opinion, either natural crossover or laboratory escape theories are plausible but we'll almost certainly never be able to prove it either way.