an option for EPUB to EPUB conversion in the Calibre-Web

[foreverlong]

Short Notice from the maintainer

After 6 years of more or less intensive programming on Calibre-Web, I need a break.
The last few months, maintaining Calibre-Web has felt more like work than a hobby. I felt pressured and teased by people to solve "their" problems and merge PRs for "their" Calibre-Web.
I have turned off all notifications from Github/Discord and will now concentrate undisturbed on the development of “my” Calibre-Web over the next few weeks/months.
I will look into the issues and maybe also the PRs from time to time, but don't expect a quick response from me.

Please also have a look at our Contributing Guidelines

Describe the bug/problem

Some EPUB files do not meet Amazon's standards. While Calibre on PC can convert EPUB to EPUB, the web version currently does not have an EPUB to EPUB conversion option in the book conversion settings. Could you please add an EPUB to EPUB conversion option?

To Reproduce

Steps to reproduce the behavior:
Go to the web version of Calibre-Web.
Navigate to the book conversion settings.
Choose EPUB option
Look for the EPUB conversion option.
Notice that it is missing.

Logfile

Add content of calibre-web.log file or the relevant error, try to reproduce your problem with "debug" log-level to get more output.

Expected behavior

I expected to see an option for EPUB to EPUB conversion in the web version of Calibre-Web.

Screenshots

If applicable, add screenshots to help explain your problem.