|Allowed Values:||0 or 1|
|Default Value:||Field is omitted if not used|
|Function:||Indicates the Unit is capable of Building the item identified in BuildType|
|Examples of Use:||Every Build Action which can be performed has this set|
This field honestly seems completely useless. If you don't want a unit to build something, you just don't list that Build Order. The only potential use I can imagine is to allow for other effects to temporarily disable a Unit's access to certain Build Orders, and easy return to the default capabilities when the effect is cleared.