Each zip package (ggml-model_name-models.zip) contains the following:
ggml-model_name.bin
ggml-model_name-encoder-openvino.xml
ggml-model_name-encoder-openvino.bin

ggml-model_name.bin are the OpenAI Whisper models converted to ggml format.
ggml-model_name-openvino.xml/.bin are the OpenAI Whisper encoder models converted to OpenVINO IR format, using convert-whisper-to-openvino.py conversion script, found in whisper.cpp repo.