Got it!
Add this to the start of the file
mnt/ext1/system/config/desktop/view.json:
Code:
{
"version": "5",
"applications": {
"U_Koreader": {
"path": "/mnt/ext1/applications/koreader.app",
"title": "KOReader",
"icon": "/mnt/ext1/applications/icons/koreader.bmp",
"focused_icon": "/mnt/ext1/applications/icons/koreader_f.bmp"
},
"_comment": [
...
Then add:
"U_Koreader",
to whichever group list you want the icon to appear in further down the file.
If it's the last entry in the section no comma at the end:
"U_Koreader"
All apps listed before it
MUST have a comma however.