The Companion Drones 2.0 (2.0.2) mod has generated a non-recoverable error.
Please inform the author of this error.

Error when executing the companion-drones::on_player_placed_equipment event (ID 41)
LuaEquipmentGrid does not contain the unit_number key.
stack traceback :
[C]: in the ‘index’ function
__companion-drones/script/companion.lua:1288 : in the ‘handler’ function
core/lualib/event_handler.lua:47 : in function <core/lualib/event_handler.lua:45>

I got the same error. Happened after adding another battery to my armor.

The mod Companion Drones 2.0 (2.0.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event companion-drones::on_player_placed_equipment (ID 41)
LuaEquipmentGrid doesn't contain key unit_number.
stack traceback:
    [C]: in function '__index'
    __companion-drones__/script/companion.lua:1288: in function 'handler'
    __core__/lualib/event_handler.lua:47: in function <__core__/lualib/event_handler.lua:45>

Fixed in 2.0.3

Wow - you are very fast with error-fixing and response!
Many thanks - you are my hero!