VMS Help RMS, XABDAT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    On Alpha systems for Files-11 B (ODS-2) media, the date and
    time XAB (XABDAT) block provides extended control of the date
    and time of the file's creation, revision (update), backup, and
    expiration.

    The following table lists the symbolic offset, the size in bytes,
    FDL equivalent, and a brief description of each field.

                        FDL
    Offset      Size    Equivalent     Description

    XAB$Q_BDT   8       DATE BACKUP    Backup date and time
    XAB$B_BLN   1       None           Block length
    XAB$Q_CDT   8       DATE           Creation date and time
                        CREATION
    XAB$B_COD   1       None           Type code
    XAB$Q_EDT   8       DATE           Expiration date and time
                        EXPIRATION
    XAB$L_NXT   4       None           Next XAB address
    XAB$Q_RDT   8       DATE           Revision date and time
                        REVISION
    XAB$W_RVN   2       FILE           Revision number
                        REVISION