[kovidgoyal]

I see lots of concern over a non-issue here. As I said before this tool will be a replacement (upgrade) for the Tweak Book functionality in calibre, it will not use code from the conversion module, but instead from the Polish Books module. That code is designed to make minimal changes to the markup/css, unlike conversions. Start up calibre and run Polish Books on a couple of epubs and see what happens.

And the tool will be launch-able as a standalone program without the need to use the library part of calibre, just like all the other tools in calibre. For example, ebook-convert.exe, ebook-viewer.exe, lrfviewer.exe, ebook-polish.exe, fetch-metadata.exe, ebook-meta.exe

And let me just say, it's obvious after all this time, from the fate of this thread and the one before it, that that there is no interest in maintaining the current Sigil codebase. Therefore, while I appreciate that some people want to hang on to Sigil or the concept of "separate" programs or whatever, the choice at this point is simple: Either we go with my offer, or the ability to conveniently tweak ebooks in EPUB/AZW3 using open tools, in a cross platform form manner, stagnates and eventually dies. While that's not a big deal to me personally, as I dont use Sigil anyway, I still think it is important, thus the offer.