This study sought to assess the effects of a salt substitute (62.5% NaCl, 25% KCl, and 12.5% flavorings) on incidence of hypertension and hypotension among older adults with normal blood pressure.
https://www.sciencedirect.com/science/article/abs/pii/S0735109723082633?via%3Dihub
So the salt alternative is mostly salt and rock salt?