According to this announcement by the late Mark Thomen:
https://listserv.ua.edu/cgi-bin/wa?A2=ind0201=ibm-main-archives=0=D===425524
the corresponding field GDGALTDT has been added to the Catalog Search Interface
for z/OS 1.3 .
The catalog field has probably existed before.
Klaus Stanislawiak
>From "DFSMS Access Method Services for Catalogs" (z/OS 1.13 version)
LAST ALTER DATE-The julian date (.DDD) on which the GDG base was last
altered, by adding or removing a GDS.
I have no idea what a value of .000 indicates, probably have to look in
some control block listing to find.
