The title is clickbait. They've found something that seems to be true for all synapses (even though the article is too vague to make that out, and it only seems

The title is clickbait. They've found something that seems to be true for all synapses (even though the article is too vague to make that out, and it only seems to be valid for pyramidal cells; these are important though), and it's about some aspect of plasticity: synaptic change can be predicted from calcium levels. This is not a learning rule, but a small part of the learning process. It also seems to offer a new direction in learning research, namely the influence of one synaptic change on other synapses. So it's interesting, but at a very technical level.