Pidgin's icon has been borrowed as the add-on's icon― and protocol icons
are taken from `$DATA_DIR/pixmaps/Pidgin/protocol/`, just as
Pidgin/libpurple installs them.
Any third-party plugins will also install their icons there, even
if just locally.
I've updated the libpurple package to include these icons, hopefully
that'll get merged.
Jaidyn Ann