FreeFileSync is distributed in various editions (as of 2024-02-06) namely:

 - Standard edition
 - Donation edition
 - Business edition

More information can be found at: https://freefilesync.org/faq.php#editions

This package is based on the source code distributed by Zenju on the website
of the application at https://freefilesync.org/ which is very close to the
Standard edition. Actually, some sensitive information are not distributed in
that source code.

Some modifications are applied to the original source package. The changes
visible to the end user are:

 - deactivate "Google Drive" feature. The credentials required to authenticate
 with Google's servers are not distributed in the source package.

 - disable automatic check for updates (as required by the Debian policy)

 - add a suffix " for Debian" in the "About" window. This permits one to
 differentiate it from the binary package shipped by upstream.


Concerning the Google Drive deactivation, if you need this feature you can:

 - use the official binary version shipped on https://freefilesync.org/
 (either Standard, Donation or Business)

 - rebuild this package yourself by specifying the credentials required by
 google's servers to start OAuth2 negotiation. These have to be set in the
 source code of FreeFileSync at this location:

    File: FreeFileSync/Source/afs/gdrive.cpp

    Functions:
      getGdriveClientId() { return ...}
      getGdriveClientSecret() { return ...}

 Please note that these are not the credentials of your Google account, but
 credentials for the application. See also

    https://developers.google.com/identity/protocols/oauth2


Known bug on backports that use wxwidgets 3.0 + gtk 3
-----------------------------------------------------

Bug #1063469: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1063469

   If your screen resolution is 1024x768 (or any other width but a height of
   768) and if you use the default Gtk theme named Adwaita you may encounter
   a crash when opening the options window (Tools menu | Options). It is
   likely this is in relation with wxwidgets-3.0 + gtk3 + some specific
   theme installed. It seems related to computation of the sizes for display
   on screen. Maybe this happens in other conditions or screen resolutions
   depending on your theme and layout.

   The workaround is to use another GTK Theme (another than Adwaita). It
   works with Numix, Yuyo, Greybird... The command would be (provided you
   have installed the package for it: numix-gtk-theme).

      GTK_THEME=Numix FreeFileSync

   Alternatives are also presented in the bug report #1063469