It would be nice to have an icon for the mod in the Steam Libray for the people who downloads the Full Mod Package instead of an empty icon.

To make this works, you need to modify liblist.gam and add the icon keyvalue like this and add these .tga files inside ag folder.
ag_icons.zip
// Valve Game Info file
// These are key/value pairs. Certain mods will use different settings.
//
game "OpenAG"
url_info "http://openag.pro"
url_dl ""
version "Dec 30 2017"
svonly "0"
type "multiplayer_only"
cldll "0"
mpentity "info_player_deathmatch"
gamedll "dlls\ag.dll"
gamedll_linux "dlls/ag_i386.so"
secure "1"
icon "agicon"
It would be nice to have an icon for the mod in the Steam Libray for the people who downloads the Full Mod Package instead of an empty icon.

To make this works, you need to modify
liblist.gamand add theiconkeyvalue like this and add these .tga files insideagfolder.ag_icons.zip