Open weights are not open source

I’ve been quantizing Gemma 4 and it’s MTP drafters recently. The next two posts are about how that went. This one is about why it was so much work. When a lab releases a model under an open license, what they almost always release is the weights. Sometimes a tokenizer. Occasionally a short technical report. Rarely the training data, data-processing code, training code, evaluation harness, or the…