What is the meaning of the %% Operator. I am unable to understand how it works.

I just tried to evaluate some random examples with the same but couldn’t find it. Can anyone please explain how is this %% Operator working in R without any symbol in between?

a <- c(1,2,3,4,5,6)

b <- c(4,5)

d <- b %% a

d

[1] 0 1 1 1 4 5

b <- c(1)

d

[1] 0 1 1 1 4 5

d <- a %% b

d

[1] 0 0 0 0 0 0