The Kwik format was designed to be used with the suite of spike-sorting and analysis tools based around KlustaKwik. It is also based on HDF5. It has since been abandoned by the developers of KlustaKwik, for the reasons outlined here. We'll continue to support the KWIK format for Open Ephys data, but we'd recommend moving away from it if you can.
The complete specification (created by Ken Harris' lab at UCL) can be found here. Open Ephys uses a variation on this specification for two reasons:
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