Gui opens when mod is installed or on reconfigure. Default key (CONTROL + R) is shown in lower left, or unknown key.
Open a stop or combinator to record it in the GUI. Forgot to mention that in the changelog.
Read from indexed wagons assigned to constant combinators:
 Completely empty spaces.
 Empty spaces and empty stack room
 Current inventory.
Wagons: 1-5 and nil to "empty" a combinator's memory.
The connection is "wireless", and only one combinator can be assigned per wagon index. When train stops in station, combinator turns on and starts outputting, and when train leaves station, station dies, wagon dies, etc, combinator is turned off. Most of the actions are trigger-driven, so to simplify code, a cleaning function sweeps through every half-hour to check for invalid entities, instead of finding every condition the entities could die/become invalid. There is normal detection for invalid entities where needed, and table mostly cleans itself automatically.
Note: there is no detection of entities moving surfaces, being cloned/moved, etc. Don't expect this to work with mods that do that: Warptorio's main platform would be the first that comes to mind.
Uses locale strings where possible. Otherwise english.