This bug part of this bug [Resolved] Custom attributes don't deletes from code
Some of the attributes of the old sites that were deleted before the fix of this bug is still present in the code. Though in the editor they are not present. We have again to add them and remove again. Only then they are removed from the code.
Example - http://take.ms/1ewnm
Here is my site Read-Only: https://preview.webflow.com/preview/wtw-5?preview=b4b10184178e7c1ee2dd0314cb020a7e