Originally Posted by jackie_w
I take it you didn't read my previous post. Sigil is a very good tool for ad-hoc epub editing, but you will see that I listed a couple of things that Sigil didn't automatically clean up for me, namely css files which were no longer referenced and items in the opf <guide> which referenced deleted files. Nor did it automatically remove images which were no longer referenced, nor remove unwanted items from the .ncx file. Luckily, 'Modify epub' does both of the latter.
That's what FlightCrew is for. It will find these things so you can fix them. I know an automated tool can handle a lot of these things. But, what if you find out after you've split your ePub that you've left bits out because you didn't see the shared files. I've done splitting manually (before Sigil) and yes, most of the omnibus editions have shared files that are not obvious from the filenames. Unless this plugin supports viewing of files, it won't work well enough overall.