Like the others already explained, "vira-latas" is a portuguese term for a stray dog and the idea that they need to flip trash cans to try to find food.
However, there is also an expression (whose origin was also explained) that means "Mongrel complex (Complexo de vira-Lata in Portuguese), which is an expression used to refer to a collective inferiority complex felt by some Brazilian people in comparison to Europe or the United States."[0]
Contrary to what was said here, the term coined by Nelson Rodrigues was not exclusive related to soccer. According to him: "By "Mongrel Complex" I mean the inferiority in which Brazilians put themselves, voluntarily, in comparison to the rest of the world. Brazilians are the reverse Narcissus, who spit in their own image. Here is the truth: we can't find personal or historical pretexts for self-esteem."[0]