[2] It serves as a receipt book for the person's "voluntary taxes" to the CTA, and has been described by a CTA official as "the passport of the exiled Tibetans to claim their rights from the Tibetan Government in Exile".
On 3 March 2005 an updated Green Book format was launched by the CTA's Department of Finance; the document holders data are stored in a computer database that had been created in a project that had started two years previously.
"[7] For this purpose, CTA defines a Tibetan as "any person born in Tibet, or any person with one parent who was born in Tibet", and, as Tibetan refugees often lack documents attesting to their place of birth, the eligibility is usually established by an interview.
[8] Before the issuance of the book, one is expected to pay an annual "voluntary tax" to the CTA.
[citation needed] According to the CTA, the Data Unit of the Department of Finance manages the central database of Green Book holders.