MarsSeed [1] filed a deletion request for qtcreator-src [2]: Old, unneeded development source package for qtcreator 8.x. Repo carries qtcreator 11.0.1, and also the qtcreator-devel package, which contains the source files needed for plugin build and development. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/qtcreator-src/