[...]point to our custom projectiles file which would be located at:
/mods/<modname>/lua/blankprojectiles.lua
It would be located it there in case you create the file !
Crate a textfile inside your mod folder:
/mods/<modname>/lua/textfile.txt
then rename the textfile to blankprojectiles.lua
Now you have your empty projectile in
/mods/<modname>/lua/blankprojectiles.lua