More than two decades have elapsed since the discovery of $\chi_{c1}(3872)$. For this meson,
previously denoted as $X(3872)$, an impressive amount of theoretical and
experimental studies has been devoted concerning its properties, decays and production
mechanisms. Despite the extensive work, a full understanding of the nature of
$\chi_{c1}(3872)$ is missing.
I describe a theoretical framework based on the heavy
quark large mass limit to analyze the radiative decays of heavy quarkonia, in
particular the electric dipole transitions of $\chi_{c1}(2P)$ to $S$-wave
charmonia. The results favorably compare to recent LHCb collaboration measurements for
$\chi_{c1}(3872)$, if this meson is
identified with $\chi_{c1}(2P)$.