I admit not having read the whole thread before asking
Is there a way to tell Sigil to
not append a ToC at the end of an EPUB?
I don't mind saving it as either EPUB2 or EPUB3.
NO View > uncheck ToC (Alt+F3)
NO LHS tree > Text > TOC.xhtml : delete
NO Tools > ToC > Edit: Delete
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Edit: Making the nav.xhtml file empty is a work-around, but if there's a less kludgy solution…