  Let G be a connected reductive complex affine algebraic group, and let X
denote the moduli space of G-valued representations of a rank r free group. We
first characterize the singularities in X, extending a theorem of Richardson
and proving a Mumford-type result about topological singularities; this
resolves conjectures of Florentino-Lawton. In particular, we compute the
codimension of the orbifold singular locus using facts about Borel-de
Siebenthal subgroups. We then use the codimension bound to calculate higher
homotopy groups of the smooth locus of X, proving conjectures of
Florentino-Lawton-Ramras. Lastly, using the earlier analysis of Borel-de
Siebenthal subgroups, we prove a conjecture of Sikora about centralizers of
irreducible representations in Lie groups.
