Could you expand this comment to include information about the high-level design of this table as well? Some things which I think should be mentioned:

* `hashes[i] == 0` implies that the `i`th slot is empty, where as not 0 implies that it's full
* `FullIndex` and `EmptyIndex` and how their proof is required whenever reading/writing values in the table.
* A detailed reason for unzipping. The comment above is good, but it doesn't go into much detail about why things are unzipped.