btw thanks for the links
I literally said this isn't a bug, now please read.
This is NO bug as all appearing splash texts are saved in one file (version.jar\assets\minecraft\texts\splashes.txt, can just be oppened trough a zip program like 7Zip), the "Finally complete!" splash text is in the file, too. So this Works As Intended.
Can confirm for 19w11a
It didn't work for me because when I did cmd O and changed the file name, nothing showed up.