LOL, well she is a "full Brindle!" Reverse Brindle, is the where the "Myth of Black Boxer's." comes from. The Gene for the color Black , does not exist in the Boxer Gene Pool. Reverse Brindle's are Brindle's but the Black is strips are more obvious. But in the right light, the brown strips will show thru.
We have a few "Reverse Brindle's," on here but they are fairly rare. But hey people do stuff. If one wanted to "create a rare," Black Boxer ... they could. A Black Lab and a Boxer, would produce a rather, odd looking Boxer or Lab I would imagine? But if you then take the pups and keep breeding them to Boxer's ... in a few "Generations," you'd have a "Black Boxer!"
Now those dog's could fool JQP, but they won't fool the AKC!
You could not show a "Black Boxer," in the AKC, because such a dog does not exist, same thing with the miniature Boxers?
According the rules Per the AKC ... such dog's do not exist as Boxer's! Embark ... would rat them out! But hey people do stuff? And one of the newest entries to the AKC, the "Dogo Argentino," has "Boxer," in there DNA!
It was a "choice," made by the creators of the "Breed, Decades Ago," they wanted a "Family Friendly Dog," so they added in Boxer's ... uh despite the "Boxer's Small Feet!"
Yeah that is a "thing." Find a "Safe Working Line GSD," (Good Luck with that ... ) and compare there feet? And you will say oh wow??? Inside info I suppose??
Anyway ...if you see other "Boxer's" around your area that are so much larger than your girl ... now you know why!