Some parts of interest:
Relieving the siege of Gaza is not the reason for creating the idea of tunnels "but profit only and nothing else" says Abumahmod, owner of a tunnel that collapsed for no apparent reason. He said that the proof is that drilling of the first tunnel was in in 1994 by one of the most famous families in Rafah, a Palestinian family, "in order to smuggle goods across the border as it happens on the borders between many countries in the world."
Abusaúb says sources of goods that enter Palestine are between three countries, namely China, South Korea and Turkey, as well as Egyptian goods. Palestinian merchants travel to those countries, and transfer the goods to Egypt to then be transferred into Gaza through tunnels...
[Another] revealed that the tunnels are used to transport all goods, regular and non regular, including forbidden items such as drugs and weapons, and noted that some tunnel owners recently had started transporting Israeli goods to be sold in Egypt through the tunnels, "as some Egyptians prefer." Many of the Gazans who sell them boast about Israeli products in their shops.