Quoting Stephan Seitz (stse+devuan@???):

> As far as I know chkconfig was never a Debian tool. I only know it
> from RPM distros. Maybe someone tried to include chkconfig in
> Debian, but gave up later. Or it never really worked.

It may be of interest that the Red Hat 'chkconfig' was a
reimplementation of the SGI Irix tool of the same name. (That's where
Red Hat devs got the idea.)

The recommended Debian equivalent has always been update-rc.d, although
some folks prefer sysv-rc-conf .

I'm not sure why chkconfig got dropped in recent (post-jessie) Debian,
but it probably has something to do with them favouring systemd's
systemctl, instead. chkconfig _was_ a Debian tool in the sense of being
available as a supported package from April 2008 until Debian 9
'stretch' came out.