I learned about Elligator quite recently and was shocked by how rarely it's actually been deployed (or even implemented), very happy to see it being used here.
Elligator is both very cool and surprisingly less useful than one might expect. It does what it promises, but there really aren't all that many situations where it's really important to conceal the fact that you're exchanging Curve25519 keys.
The most common encrypted protocols advertise the cipher suite they're using, so there is little value in concealing the format of the keys being exchanged. And protocols trying to hide their existence entirely are pretty uncommon.
> Release date: 4/20/2018
> Revision date: 10/8/2018
Would be nice to get a (2018) in the title.