You can find the published source code at github.com/wireapp.
For licensing information, see the attached LICENSE file and the list of third-party licenses at wire.com/legal/licenses/.
The roles of the axolotl protocol for a particular session are fixed through the use of prekeys:
The side that obtains a prekey and uses it to initiate a session is Alice.
The side that receives a prekey message and uses it to initiate a session is Bob.
All cryptographic primitives used in the implementation of the protocol are provided by libsodium: