When a download is failed, re-downloading should continue the download where it left out last time. Also it will be good if there's a retry dialog when download is failing:
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- 0:00:19 --:--:--
curl: (6) Could not resolve host: raw.githubusercontent.com
Download failed. Retry [Y/n]:
When a download is failed, re-downloading should continue the download where it left out last time. Also it will be good if there's a retry dialog when download is failing: