office.microsoft.com/.../HA010548161033.aspx

In my Excel 2003, it seems to have gone to Excel11.xlb. Not inherently
shareable, unfortunately.

However, you could create it dynamically. E.g. this is me creating a test
one:

Option Explicit

Sub Macro1()
'
' Macro1 Macro
' Macro recorded 12/03/2008 by xxx
'

'
Application.CommandBars.Add(Name:="Freddie").Visible = True
Application.CommandBars("Freddie").Controls.Add Type:=msoControlButton,
ID _
:=106, Before:=1
Application.CommandBars("Freddie").Controls.Add Type:=msoControlButton,
ID _
:=3, Before:=2
End Sub

You could perhaps make this conditional on whether it already exists or not.