MarsSeed [1] filed a deletion request for kaption [2]: Broken, abandoned KDE4/Qt4 application package from 2018.
Its source is unavailable (server connection timeout). Also it depends on the nonexistent 'kdebase-runtime', and omits the necessary 'qt4' dependency. Last comment is from Feb 2019. Popularity: 0.000000. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/kaption/
