DMLC is an acronym that stands for:
- Distributed (Deep) Machine Learning Community
DMLC was a research group at the University of Washington (UW) and was the source for important machine learning projects such as XGBoost and MXNet primarily drive by Tianqi Chen, then a Ph.D. at UW.
You can learn more about DMLC here:
The DMLC group appears to be no longer active, but the projects it spawned do remain active.