Chazza [1] filed a deletion request for libical2 [2]:

I added this package as a stopgap to allow kdepimlibs4 to build as it wouldn't build against libical version 3. However, there's now a patch which allows kdepimlibs4 against the new libical version which means that this package is now useless.

[1] https://aur.archlinux.org/account/Chazza/ [2] https://aur.archlinux.org/pkgbase/libical2/