Describe your suggested feature

It is from an epub with chapters from chap 1 to chap 10.
The files should be numbered
01
02
03
and so on (some novels might have the chapter 00)

Other details

When the chap number is higher like 450 it appears like this:

these are chapters numbered from 455 to 464

Acknowledgements

• I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open or closed issue.
• I have written a short but informative title.
• If this is an issue with a source, I should be opening an issue in the sources repository.
• I have updated the app to version 1.1.14.
• I will fill out all of the requested information in this form.