As an avid StarCraft player I still think AlphaStar is one of the most impressive AI programs ever made. While it didn't get everything quite right, it exhibited planning and creativity in it's builds, and didn't just do the same exact thing every time; it scouted and reacted to the opponent's moves with professional-level proficiency.
AlphaStar's training process consisted of two phases: an imitation-of-human-players learning phase that created a base set of "templates" and then self-play among agents seeded from those templates.
When creating those templates, they basically ended up with "baked-in" build orders. But self-play among agents ended up creating a variety of reactive strategies on top of those build orders, so that agents would modify them on-the-fly as the game situation changed. At a high level this is basically how humans use build orders as well.
