Laminar is a crate, located here: https://github.com/amethyst/laminar. It is the lowest level crate used for networking in the Amethyst engine, though it is not tied to Amethyst and can be used independently.
As an application developer, you will not have to deal with this crate unless you have very custom needs. The details of how this crate works can be found in its README. A brief summary is that it is a UDP-based protocol with a bit of fragmentation and reliability support layered on top.
This crate is maintained by the Amethyst Networking team. As it is a fundamental crate, our primary goal for it is stability and reliability.
If you do have questions about it, please feel free to post here. We love talking about networking. =)
0.1.0 was just released. The crate is not yet considered stable; our next cycle of work will be to start building higher-level abstractions on top of it.