Any news on the restoration of the briefcase feature?

I've noticed that both threads discussing the Briefcase feature are somewhat dated, and there are open topics regarding its restoration.
I wanted to inquire if there are any updates or insights on how to fully restore Briefcase functionality.

I've managed to restore the Briefcase icon successfully, but the other functionalities haven’t worked as expected.
Additionally, I found that in Windows XP, the command

C:\WINDOWS\system32\rundll32.exe C:\WINDOWS\system32\syncui.dll,Briefcase_Create 65682 <Path>
can be used to create new Briefcases.
What I question is what the number in the command does.

Furthermore, I’ve explored the shell new handlers. After importing the shell new handlers from both Windows 7 and Windows XP x64, they do not appear in the context menu, even though they are listed by ShellNewHandler as enabled.
Same for .contact btw.

Links to old threads:
winclassic.net/thread/1369/restoring-briefcases-context-menu-desktop
winclassic.net/thread/1120/adding-briefcase-functionality-back-windows