MarsSeed [1] filed a deletion request for headphones [2]: Seems like this is obsolete software, barely maintained by upstream. As it depends on both the frequently broken EOL gstreamer0.10, and also on qt5-webkit that is EOL since 2017 and has mostly been broken since May 2024.
(All qt5-webkit packages on AUR are unbuildable: qt5-webkit, qt5-webkit-git, qt5-webkit-movableink-git.) [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/headphones/
