Originally Posted by crutledge
Add Semantics only determines what goes into the <guide> section of content.opf and works fine. The missing line is in the meta data.
If I understand meme's comment correctly, this is not the case. "Add Semantics" adds some needed tags where needed:
If you designate an HTML as a cover document, Sigil will add a line to the <guide>.
If you designate an image file as a cover file, Sigil will add the <meta> tag.
Note that the <guide> should only contain links to HTML files, and that the <meta> tags are not standardized:Kindlegen uses it, other software may use it too, but there's nothing in the spec that says what its effect should be, actually, there's no "cover" in the epub spec.