This is not really a debian package, just a script to call make-kpkg to build the ev3dev kernel and modules.
It is for building official releases. If you just want to compile the kernel, see https://github.com/ev3dev/ev3dev-buildscripts.
IMPORTANT: Requires patched version of kernel-package due to
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=890817. This is available
in the ev3dev tool PPA for Ubuntu 18.04.
Build depends: kernel-package devscripts module-assistant gcc-linaro-arm-linux-gnueabihf-6.4
Toolchain package is in ev3dev PPA:
sudo add-apt-repository ppa:ev3dev/tools