The script is intended be used for simpler migration from a single control.lua file to libs with Factorio's builtin lualib.event_handler.
Single file:
-- control.lua
script.on_init(on_init)
script.on_configuration_changed(on_configuration_changed)
script.on_event({defines.events.on_built_entity, defines.events.on_robot_built_entity}, handler1)
script.on_event(defines.events.on_entity_died, handler2)