On the on-line hosted version of swagger-editor
set your host to be localhost:7080 for example
the "Learn more" link is down when refering to CORS
鈿狅笍 This is a cross-origin call. Make sure the server at localhost:7080 accepts GET requests from editor.swagger.io. Learn more

EDIT: Currently points to:
https://github.com/swagger-api/swagger-editor/blob/master/docs/cors.md
Thank you for pointing that out. In the mean time, the link to the document is https://github.com/swagger-api/swagger-editor/blob/2.x/docs/cors.md.
We're not going to fix this issue.
@webron would you mind clarifying what you mean by not fixing the issue? Do you mean there won't be such a link in the future, there won't be such docs in the future, or the link will always be broken?
The link will be broken. It only exists in the 2.X version and doesn't exist in the 3.X version. We're not going to release a new 2.X version unless we find something insanely critical.
@webron Thanks so much for the quick and helpful reply and also all the work you do :)
Most helpful comment
The link will be broken. It only exists in the 2.X version and doesn't exist in the 3.X version. We're not going to release a new 2.X version unless we find something insanely critical.