POLORalph Lauren Underwear Men's 3 Pack 4D-Flex Lux Cotton Blend Boxer Briefs, Polo Black, XL

Do these have a seam in the back down the middle?

What does convenient fly front mean I'm not seeing a button or zipper? I have ones with button fly and polo player icons. 55cotton/45modal. No spandex

What size?

How long