Back to Adam and Eve.
After eating the forbidden fruit, they knew that they were naked; and they sewed fig leaves together, and made themselves aprons. (Genesis 3:7)
God wasn't fooled, of course and today a fig leaf refers metaphorically to something that conceals or camouflages (usually inadequately or dishonestly).
Fig leaves can also be used more literally. For example, art restorers in Italy long ago discovered that fig leaves in paintings and sculptures aren't always original. Sometimes they were added, centuries later, to conceal offending nudity.