Mark Zanger wrote: << I would guess that the green peppers were also pickled,
and called mangos by analogy like the cukes. >>

In the Cincinnati Recipe Treasury (Ohio University Press, 1983; p. 213) there
is a 1938 Hamersville, Ohio, letter which mentions "mango pickles" and on the
following page a recipe from Hamersville for "Mango Pickle."

In the recipe, green peppers are soaked overnight in salted water, then stuffed
with ground cabbage and pickled in a vinegar, sugar, mustard seed "syrup."

Robert