This Information Request was dealt with by phone. A summary of the response follows:
1.

This type of bomb is known in Latin America as "bomba pafletera" (pamphlet bomb). The explosion objective is not to cause harm but to alert and direct the people toward a pile of leaflets announcing a milestone political occurrence.
2.

This technique is mostly used by left-wing political organizations. Most guerrilla movements announce their formation or alliances this way.

THIS RESPONSE IS FOR THE RECORD ONLY AND NOT TO BE SENT OUTSIDE THE DOCUMENTATION CENTRE