  We investigate additional properties of protolocalizations, introduced and
studied by F. Borceux, M. M. Clementino, M. Gran, and L. Sousa, and of
protoadditive reflections, introduced and studied by T. Everaert and M. Gran.
Among other things we show that there are no non-trivial (protolocalizations
and) protoadditive reflections of the category of groups, and establish a
connection between protolocalizations and Kurosh--Amitsur radicals of groups
with multiple operators whose semisimple classes form subvarieties.
