https://en.wikipedia.org/wiki/Solar_gravitational_lens
Authors. Wikipedia
Venue. — tertiary retrieval path
How the Institute flags it
speculative 2 times frontier 1 time
This source carries more than one flag across the corpus. That is not an inconsistency to resolve: the same work can be established evidence for one claim and frontier evidence for another, and the flag belongs to the use rather than to the source.