GPE-Cal 0.73-21
libeventdb0 0.29-9
libgpepimc0 0.8-1
libgpevtype0 0.17-2
libgpewidget1 0.114-1

These are all the libraries that look GPE related. I don't see anything named libsoup.

I don't know if its relevant or not, but Cal is the only GPE app that I have installed (I don't have Contracts or Todo).