  We propose a spatially and temporally nonlocal exchange-correlation (xc)
kernel for the spin-unpolarized fluid phase of ground-state jellium, for use in
time-dependent density functional and linear response calculations. The kernel
is constructed to satisfy known properties of the exact xc kernel, to
accurately describe the correlation energies of bulk jellium, and to satisfy
frequency-moment sum rules at a wide range of bulk jellium densities, including
those low densities that display strong correlation and symmetry breaking.
These effects are easier to understand in the simple jellium model than in real
systems. All exact constraints satisfied by the recent MCP07 kernel [A.
Ruzsinszky, et al., Phys. Rev. B 101, 245135 (2020)] are maintained in the new
revised MCP07 (rMCP07) kernel, while others are added. The revision
$f_\mathrm{xc}^\mathrm{rMCP07}(q,\omega)$ differs from MCP07 only for non-zero
frequencies $\omega$. Only at densities much lower than those of real bulk
metals is the frequency dependence of the kernel important for the correlation
energy of jellium. As the wavevector $q$ tends to zero, the kernel has a $-4\pi
\alpha(\omega)/q^2$ divergence whose frequency-dependent ultranonlocality
coefficient $\alpha(\omega)$ vanishes in jellium, and is predicted by rMCP07 to
be extremely small for the real metals Al and Na.}
