diabonas [1] filed a deletion request for pdftk [2]:

pdftk has been adopted to [community] (based on the pdftk-java rewrite
instead of the original, discontinued code):
https://www.archlinux.org/packages/community/any/pdftk/

Thank you for your maintainership!

[1] https://aur.archlinux.org/account/diabonas/
[2] https://aur.archlinux.org/pkgbase/pdftk/