See ggplot2::aes() for details.
aes(x, y, ...)A list with class uneval. Components of the list are either quosures or constants.
<data-masking> List of name-value
pairs in the form aesthetic = variable describing which variables in the
layer data should be mapped to which aesthetics used by the paired
geom/stat. The expression variable is evaluated within the layer data, so
there is no need to refer to the original dataset (i.e., use
ggplot(df, aes(variable)) instead of ggplot(df, aes(df$variable))).
The names for x and y aesthetics are typically omitted because they are so
common; all other aesthetics must be named.