Because I was stupid. Just another 16M which helped to crash my system on update to 3.4.0.22. /usr/local/bin is in the small system partition. And I did not think about restic when I tried to cleanup space.

Ahem I now have put it into ~/bin and expanded PATH. This is - of course - the better solution: No devel-su needed, no system memory, better for ansible...

Sorry for that. And I may say: for recovering restic helped much.