Don't know the back story for the gtk3-immodules split. (Wasn't installed in a f14 => f15 upgrade) When I look at it: $ rpm -ql gtk3-immodules /etc/X11/xinit/xinput.d/im-cedilla.conf /etc/gtk-3.0/im-multipress.conf /usr/lib64/gtk-3.0/3.0.0/immodules/im-am-et.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-cedilla.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-cyrillic-translit.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-inuktitut.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-ipa.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-multipress.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-thai.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-ti-er.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-ti-et.so /usr/lib64/gtk-3.0/3.0.0/immodules/im-viqr.so Certainly some of those are "fluff", but im-cedilla is basically a bit of the core of GTK+ - it's the version of the default module that is used instead for languages that include a cedilla (French, Portuguese, etc.)
Will be fixed in the next build.
I didn't comment earlier, but cedilla is already covered by im-xim.so (with X compose maps), which works consistently across all X toolkits for this.