GNUser, sorry for disturbing and making so many noise.
It's an interesting discussion, not noise, so nothing to be sorry about
My two cents on the thread so far:
1. I love how conservative TCL is, and how much care goes into making sure that changes cause no breakage. This is yet another of TCL's many outstanding qualities.
2. I agree that predictability and controllability are both important. It seems that having "sort" in the /usr/local/etc/X.d line would add predictability and, for extensions where it is important, would give the extension maintainer controllability. TCL11 x86_64 repo currently has only one extension (open-vm-tools-desktop.tcz) that puts something in /usr/local/etc/X.d, so it would not be difficult for extension maintainers to coordinate in the unlikely event that execution order matters.