Weak Leibniz algebras and transposed Poisson algebras

An algebra with identities $[a,b]c=2a(bc)-2b(ac),a[b,c]=2(ab)c-2(ac)b$ is called weak Leibniz. We show that weak Leibniz operad is self-dual and is not Koszul. We establish that polarization of any weak Leibniz algebra is transposed Poisson, and, conversely, polarization of any transposed Poisson algebra is weak Leibniz.