  We complete the construction of the fundamental diagram of various partial
compactifications of the moduli spaces of mixed Hodge structures with polarized
graded quotients. The diagram includes the space of nilpotent orbits, the space
of SL(2)-orbits, and the space of Borel--Serre orbits. We give amplifications
of this fundamental diagram, and amplify the relations of these spaces. We
describe how this work is useful to understand asymptotic behaviors of
Beilinson regulators and of local height parings in degeneration. We discuss
"mild degenerations" in which regulators converge.
