The word None, entered in a field that does not apply to the case, as each field's description specifies.
Because characters are required in all requested fields unless otherwise specified, fields that do not apply are filled with the literal None as their descriptions direct. Examples include FDR when the plan processed the request itself, or a time field on a standard service request. The ODAG layouts use None; they do not use NA or TBD.
Sources: ODAG protocol, Universe Submissions, PDF p. 15; Universe Table 1, Columns F and I, PDF pp. 18-19; CDAG protocol, Universe Submissions, p. 15; e.g., Universe Table 1, Columns I, L, W, pp. 17-20; SNPCC protocol, Universe Table 1 SNPE, Column IDs H-M (PDF pp. 10-12); Table 1IA Column ID K (PDF p. 15).