Hi
Someone from the docs team has just experimented quite a bit and
written up a really quick wiki-page.
https://wiki.documentfoundation.org/EPUB
I dunno why people insist on using all capitals or putting spaces into
urls but i've had trouble in the past with trying to get a consistent
naming convention sorted out and it's led to duplicates needing to be
merged.
I know some people here have experimented with ePub quite a lot in the
past so some of you could edit the wiki to add your own findings.
Don't worry too much about layout at this point. Content is more
important at the moment.
There is not much point in going back to earlier versions of
LibreOffice = it's the future that is more of interest.
Regards from