  In this decade one expects a very significant progress in measuring the
branching ratios for several rare $K$ and $B$ decays, in particular for the
decays $K^+\to\pi^+\nu\bar\nu$, $K_L\to\pi^0\nu\bar\nu$, $B_s\to\mu^+\mu^+$ and
$B_d\to\mu^+\mu^+$. On the theory side a very significant progress on
calculating these branching ratios has been achieved in the last thirty years
culminating recently in rather precise SM predictions for them. It is then
unfortunate that some papers still cite the results for $K^+\to\pi^+\nu\bar\nu$
and $K_L\to\pi^0\nu\bar\nu$ presented by us in 2015. They are clearly out of
date. Similar comments apply to predictions for $B_{s,d}\to\mu^+\mu^-$. In this
note I want to stress again that, in view of the tensions between various
determinations of $V_{cb}$ in tree-level decays, presently, the only trustable
SM predictions for the branching ratios in question can be obtained by
eliminating their dependence on the CKM parameters with the help of
$|\varepsilon_K|$, $\Delta M_s$, $\Delta M_d$ and $S_{\psi K_S}$, evaluated in
the SM. In this context I am astonished by statements made by some computer
code practitioners that setting in this strategy these four $\Delta F=2$
observables to their experimental values is an assumption. The goal of this
strategy is not to make an overall SM fit but to predict the SM branching
ratios. In the SM there are no new physics (NP) contributions to $\Delta F=2$
transitions and no assumption on the absence of NP is needed. Moreover,
presently NP is not required to describe simultaneously the very precise data
on $|\varepsilon_K|$, $\Delta M_s$, $\Delta M_d$ and $S_{\psi K_S}$. This
strategy for obtaining true SM predictions for rare decay branching ratios is
moreover not polluted by hadronic uncertainies and observed anomalies in
semi-leptonic decays used often in global analyses as stressed recently in
(arxiv: 2209.03968).
