An implementation of the Signal Protocols X3DH and Double Ratchet. Plus a simple straightforward usable E2E encryption library build on top, named Xochimilco.
For both implementation details and examples, take a look at the documentation.
Some background, the lake Xochimilco seems to be the last native habitat for the axolotl. This salamander, also called Mexican walking fish, has incredibly self healing abilities. For this reason, the Double Ratchet algorithm was initially named after this animal.