Backup files - Documentation and usage

I noticed, especially when working with documents and configuration files that backup files are automatically created.
How is this working, by what principle, I noticed not all files are backed up when working with, is there a documentation regarding this system ?

I’m pretty sure that it is the editor that decides whether or when to backup files.

Kwrite backs up when saving. I think it is configurable for kwrite.

This is not a feature of the system, but of each and every application itself. Thus there is no general rule for it and documentation should be in the documentation of each and every application when applicable.

I understand now, I did not thought about Kwrite indeed:)

Thank you very much !