The death announcement of Google Wave happened just over three months ago. At the time the company assured that it would release the source code of the project open-source license with the name of the Wave in a Box, and provides its users a way to export the data that they put in the service. The data export was possible since last week, but there is no where to send this file yet. At least until the end Apache your version of Wave.
The Apache Software Foundation said yesterday that should redeem the code of the Wave in a Box and implement it in their own management system. So users will have a place to send the extracted data from the late Google Wave, if you will. For now the project, called Apache Wave is in an incubator foundation necessary step for the group rate necessary licenses, among other things.
Still, the Apache Wave has received support from several Google employees. The foundation did not say when to implement the code on your own system, but as Google will disable Wave at the end of the year I imagine that at least before that date it is already at least in the testing phase.