Pytorch built in debug mode

Hello there, I built pytorch from source and noticed some of my training scripts were running slower than I would expect them to. The output of a pytorch.bottleneck run has:

Environment Summary

PyTorch 1.7.0a0+8864148 DEBUG compiled w/ CUDA 11.0

This seems to suggest pytorch is built in debug mode. However, in a python shell:

In [3]: torch.version.debug
Out[3]: False

How would I tell for sure if pytorch is built in debug mode?