According to Nvidia these are former "Short Lived" branches that are no longer supported.
# Jeroen Roovers <j...@gentoo.org> (14 Dec 2018) # Deprecated short lived branches # https://www.nvidia.com/object/unix.html # File a bug report if you need to use one of these # Removal on or about 14 January 2019 =x11-drivers/nvidia-drivers-375* =x11-drivers/nvidia-drivers-378* =x11-drivers/nvidia-drivers-381* =x11-drivers/nvidia-drivers-384* =x11-drivers/nvidia-drivers-387* =x11-drivers/nvidia-drivers-396* Kind regards, jer
