"script-include-table" container
From TrainzOnline
The "script-include-table" container is a top-level config.txt file entry available to any Asset which derives from KIND TrainzBaseSpec (in short, all Assets.) This container allows the asset to directly include another asset's scripts from the parent asset's script file(s).
The extensions container is a list of custom tags or subcontainers with a specific naming convention.
Supported Tags
This container is a simple key-value table of scripted assets which are searched for script includes when compiling the asset's script file(s). The key is currently unused; the value indicates the KUID of the asset to include.
Validation
It is typically best to restrict such references to KIND Library assets, however this is not mandatory and any assets can be referenced.