The following shows how to configure an app to use Github as the update source, for Gear Lever 4.+.
Let’s use https://www.digikam.org/download as an example.
This page lists all the available FTP servers for Digikam. Let’s pick the best one for current our location.
(Files for Digikam are exposed under http and ftp);
https://mirror.gofoss.xyz/kde-ftp/stable/digikam/8.8.0/digiKam-8.8.0-Qt6-x86-64.appimage
Server URL
FTP servers must start with ftp://
ftp://mirror.gofoss.xyz
File path
kde-ftp/stable/digikam/*/digiKam-*-Qt6-x86-64.appimage