> Disclaimer: this proves integrity, not completeness (as a self-held chain proves nothing was edited but does NOT prove that nothing was omitted).

Or as the page puts it in more detail:

> A self-held chain proves integrity: nothing was edited or reordered after the fact. It cannot prove completeness: the operator of a recorder can delete the bad day and re-seal the chain, or never write a record at all, and the chain stays internally consistent.

I don't get this. If I "hold" the "chain" (I hate the jargon agents invent), why can't I edit or reorder and then "re-seal" it?