Gdebi shows a "Download Package" button when we try to install a package that is already available in some repository added in the system. It seems that this button does nothing in current versions of Gdebi, and therefore can be removed from it. The use of this button was not documented anywhere. Also, if it is a feature, it seems probably broken. So, I would suggest to remove this button and underlying broken code.
Control: tags -1 + unreproducible Control: severity -1 wishlist Norepro: $ PYTHONPATH=. python3 ./gdebi-gtk switchsh_0~20070801-1_amd64.deb & Get:1 switchsh_0~20070801-4_amd64.deb [6,244 B] Fetched 6,244 B in 0s (0 B/s) $ l -rwxr--r-- 1 nabijaczleweli users 5.6k 11-02 14:45 switchsh_0~20070801-1_amd64.deb -rw-r--r-- 1 nabijaczleweli users 6.1k 2017-01-26 switchsh_0~20070801-4_amd64.deb (unclear why it's executable, but.)