A number of special index parameters may be specified. The index type sub can be decomposed into subinitial, subany, and subfinal indices. The special type notags (or nolang) may be specified to disallow use of this index by subtypes with tagging options (such as language options). The special type nosubtypes may be specified to disallow use of this index by named subtypes. Note: changing index settings requires rebuilding indices, see slapindex(8).