I was trying out the new kfx output format. It works pretty well only thing is that the margins aren't automatically detected as black and that some pages have borders. I used this other method too to compare (https://github.com/HankunYu/kindle-comic-workaround-5.19.x). In this method the only advantage is that all pages have no borders as intended, however similarly there is not automatic detection for black borders (before using this calibre plugin I actually ran the pages through kcc with my preferred settings).
Here are two images from the kcc kfx format format with another one of my settings.
I was trying out the new kfx output format. It works pretty well only thing is that the margins aren't automatically detected as black and that some pages have borders. I used this other method too to compare (https://github.com/HankunYu/kindle-comic-workaround-5.19.x). In this method the only advantage is that all pages have no borders as intended, however similarly there is not automatic detection for black borders (before using this calibre plugin I actually ran the pages through kcc with my preferred settings).
Here are two images from the kcc kfx format format with another one of my settings.