This is a document issued by a notary in El Salvador when there is no birth certificate available. It bestows all the rights of a birth certificate.

' ... late/extraordinary registration of birth' may be options as well

Estado Familiar >> referring to matters of family law

Subsidiario >> providing relief or a solution (as seen in the 'solución' in the following definition)

"Subsidiario. Aplicase a la cuestión, solución o pretensión que se pide subsidiariamente al juez en la demanda o contestación, para el caso de que se deniegue la principal."
http://www.enciclopedia-juridica.com/d/subsidiario/subsidiar...

Government of the Virgin Islands
**Late Registration of Birth.** This service caters for customers who birth confirmation given by the Peebles Hospital and twelve months has elapsed from the ...
http://www.bvi.gov.vg/services/late-registration-birth

*Delayed Registration of Birth* - County of Fresno
https://www.co.fresno.ca.us
Application for **Delayed Registration of Birth** (VS 85 form) with the California Department of Public Health. – Vital Records (CDPH-VR).

UNIVERSIDAD CATÓLICA DE SANTIAGO DE GUAYAQUIL
by NY López Rojas · 2021 — **extraordinary registration of birth** because it is under *voluntary jurisdiction*. KEY WORDS: Law, jurisprudence, registration, birth, reforms

**Voluntary (Non-Contentious) Jurisdiction** Around The World
https://books.google.com.vn › books
Argounov V. V. · 2017 · ‎Law
... 3) the fact of registration of birth, adoption, marriage, dissolution of ... the special proceedings in court and **voluntary jurisdiction** on the whole.

DELAYED REGISTRATION OF BIRTH - City of Berkeleyhttps://www.cityofberkeley.info
APPLICATION FOR DELAYED REGISTRATION OF BIRTH. A fee is required for births registered one year after the date of event. The fee includes one certified copy ...

AFFIDAVIT FOR DELAYED REGISTRATION OF BIRTH
https://www.philcongen-toronto.com
AFFIDAVIT FOR DELAYED REGISTRATION OF BIRTH. (Either the person himself if 18 years old or over, or father/mother/guardian may accomplish this affidavit).

juridicción voluntaria = non-contentious/voluntary jurisdiction (in this case, perhaps the latter would be preferable)

Voluntary Jurisdiction Proceedings, Delayed/Late Registration of Birth

I hope this helps, Darius. Regards from Vietnam :-)