You should have. Because the code base has had it removed since 1.13.0 (28211) so whatever you’re doing must have been pretty impressive.
The scripting model was freely available to the player community and wasn’t “discovered” at all. Blizzard intentionally released a LUA sandbox for us to make addons in, and provided the /script command to execute macros in that sandbox too. And told us about it and told us to use it.
This wasn’t some secret, unless someone was specifically not paying attention to it.
If you want more technical information, see this post: