Ration card

Bashir and Sisko with Gabriel Bell's ration card

A ration card was a card issued by social workers to residents of Sanctuary Districts that was used to track food and water distribution at various points on Earth in the 21st century.

They were uniquely assigned to specific residents, but despite this, ghosts often stole the ration cards of Sanctuary District A's weaker residents. (DS9: "Past Tense, Part I")

The ration cards were issued by the "Errand of Mercy Meal Support" (a reference to the TOS episode of that name). They also give the names of two San Francisco government officials: Dave Lister and Arnold Rimmer, a nod to the British television series Red Dwarf.(citation needededit)
Since they had identification info for the resident to which they were assigned, it's unclear how ghosts were able to use stolen cards.

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