due to an upstream bug in our markdown parsing stack, offsite links don’t get rel=”nofollow noreferrer” if they’re protocol-relative.

users have reported this to the upstream package (https://github.com/rehypejs/rehype-external-links/issues/8), and a fix may be forthcoming; otherwise we need to find a workaround.

Notes

• reported by @mog, @iliana, and @lifning.
• in the new major version of rehype-external-links, the default target for external links has changed from “_blank” to undefined. if this issue is solved by an upgrade, we need to explicitly set target. — colin, 7/27