Hello,Thanks for the report. By now I prefer to wait for the resolution of the bug #902788, as it seems that it should be python3.7 that requires a Break field in its control file and as python3.6 is still the default python3 version of Sid.
Nevertheless, I will inform the mainstream maintainer about the bug in order to get it corrected in future releases and update it as soon as the patch is made.
Cheers, -- Philippe THIERRY.