Comment 1 for bug 1475995

Please open a terminal and type 'man backintime'. There you'll find a section 'user-callback'.

I can not update the documentation in backintime.le-web.org as this is owned by Dan, the inventor of BIT, who left the project.

BIT will need a complete rewrite of the documentation which is shipped with it as it is completely outdated. But I'm no good in writing docus and I'm also not very enthusiastic about it.

So until there is a new docu you'll find all necessary information in that man-page.