In rP7775, UnitAI was rewritten, among the changes made was that a foundation being finished sent a message.
Since at that time there was no way of telling which units took part in the construction, a global message was handled in UnitAI, along with a ToDo that that is expensive and unnecessary.
rP23449 Introduced a function to get the builders for both a foundation and a repairable target, which means that the messages can now be sent targeted, at least fixing the ToDo and hopefully improving performance a bit.
One thing to notice is that `Trigger.js` handles the `OnGlobalConstructionFinished`-message, which is now handled more often. However, I have observed no problems with that during the Economy Walkthrough, which I assume uses that trigger message ;)
Also the AI-interface will now process more of the same message, of which I saw no effect during PetraAI vs. PetraAI battles.