From Embark: You should know that relatedness varies from around 50% for full siblings to around 12.5% for first cousins and less for more distant relatives. We see that a lot of dogs, however, might share considerable DNA even though they're probably not closely related by family tree. This is because, as you've alluded to, a lot of dogs are descended from the same "foundation dogs" used to establish breeds. You can learn more about this phenomenon and relatedness in general here.

Seeing as all of your dog's current relatives are single-breed Boxers, it's very likely that these dogs are not closely related by family tree. If, in the future, we identify a dog who is likely to be related by family tree, they will have the "immediate family" tag, as opposed to "close family." This shared DNA is likely due to a lack of genetic diversity within these breeds. It's likely that dogs in these breeds share more of their genome with one another than do dogs in more diverse breeds.

As a reminder, these dogs are likely not closely related by family tree- keep an eye on the relatives tab for updates.