km_KH.UTF-8 Compose file is superfluous
https://gitlab.freedesktop.org/xorg/lib/libx11/blob/master/nls/km_KH.UTF-8/Compose.pre includes include "X11_LOCALEDATADIR/en_US.UTF-8/Compose" and then only adds five compose sequences which are already contained in the en_US.UTF-8 Compose file. See: https://gitlab.freedesktop.org/xorg/lib/libx11/blob/master/nls/en_US.UTF-8/Compose.pre#L5162
Therefore, the file https://gitlab.freedesktop.org/xorg/lib/libx11/blob/master/nls/km_KH.UTF-8/Compose.pre is superfluous.