So my build — the 'debian way' — of #Enlightenment 0.24.1 https://www.enlightenment.org/ failed to build the screen backlight amongst a couple more modules. Thus while I find out what went wrong I still installed my newly built #E24 and with sudo or acquiring root privilege:
apt-get install brightness-udev brightnessctl

…subsequently, via sudo or acquiring root privilege I typed the command:
brightnessctl set +50%

It brightened my screen by 50% over the current opaque state.😎 Read:
man brightnessctl