GitHub now supports 451 status code for DMCA blocked content

The 451 status code is now supported | GitHub Developer Guide

GitHub now returns a 451 HTTP status code for repos that have been blocked/removed due to a DMCA notice.
The new 451 code should be used in place of a generic 403 to indicate that content is not available for legal reasons. The reason is likely to be a DMCA notice, but could be used for content that has license restrictions, or other legislative or regulatory blocks.