MarsSeed [1] filed a deletion request for nausoftphone-plugin-cef [2]: Unneeded, abandoned plugin from 2017 for the defunct Qt4 and webkit based nausoftphone binary client.
Upstream seems to no longer provide that VOIP telephony app separately. Instead, it seems to have been integrated into its "Naumen Contact Center" product. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/nausoftphone-plugin-cef/
