Official "Subfiles" That are not longer used

[Steffen]

May I suggest that we extend the LDRAW syntax to make the obsoletion recognizable by tools?

Possible solutions:

(A)
extend
0 !LDRAW_ORG Unofficial_Shortcut
syntax to
0 !LDRAW_ORG Unofficial_Shortcut (Obsolete)

or

(B)
introduce a new meta
0 !OBSOLETE