@Doitsu as reply to your post #19
Thanks again for your time and all the helpful hints.
I understood how to deal with "undo" now.
Great tip with the zip/unzip App. Works perfectly.
I deleted the NCX file and deleted the appropriate references in the OPF.
Than I zipped everything with the app: it validates with
http://www.pagina-online.de/software/epub-checker/
But when I open the EPUB in Sigil, it automatically adds a NCX.
Is there any way to prevent that in Sigil?
Ditto for the entry about the Sigil version in the meta element.
About the folder structure:
OK, I like Sigil a lot and want to use it for editing. So I have to live with the fixed folder structure.
I reached the target of a minmal epub almost - mainly because of your hints
Well, I need to test, what the Kobo will do with such a minimal epub3.
I hope there will be a solution for Sigil to keep it prevent that automatically generated NCX.
Are there strong reasons against the idea to place the complete content into one single file (title, content, about, imprint)? Will that cause problems in a Kobo? I think of inserting automatical page breaks in front of specific headings via CSS. Than there's no need at all for separated files for the content.