Global index for numbered names.
We maintain a global index for numbered names, which is initially 1 and can be incremented by 1 or reset to 1. This global index is stored in a table.
This global index can be used, for instance, to support the generation of successive sets of numbered names such that the names in each set have the same index and the index is incremented from one set to the next set.
This global index is not used by next-numbered-name, which increments the index in a more “local” way.