  Stable micro-nucleus is 2-flavored (u and d), whereas stable macro-nucleus
could be 3-flavored (u, d and s) if the light flavor symmetry restores there.
Nucleons are the constituent of a nucleus, while strangeons are named as the
constituent of 3-flavored baryonic matter. Gravity-compressed baryonic object
created after core-collapse supernova could be strangeon star if the energy
scale (~0.5 GeV) cannot be high enough for quark deconfinement and if there
occurs 3-flavor symmetry restoration. Strangeon stars are explained here,
including their formation and manifestation/identification. Much work, coupled
with effective {micro-model} of strangeon matter, is needed to take advantage
of the unique opportunities advanced facilities will provide.
