Something I have found:
1. Found a decompiler for Line.pbt which is the pocketbook theme located in /ebrmain/themes. I downloaded the Windows zip version from this this link
https://github.com/Lighting/pbtheme/releases/tag/v2.2.0
2. Ran this command in CMD to decompile the file Line.pbt
pbtheme -e Line.pbt >output.txt
3. In the output.txt file I found
desktop.launcher.shortcut.1.position=99,1304,384,1 14
desktop.launcher.shortcut.1.text=@Library
desktop.launcher.shortcut.1.path=/ebrmain/bin/explorer.app
desktop.launcher.shortcut.1.icon=desktop_launcher_ library
desktop.launcher.shortcut.1.icon.focus=desktop_lau ncher_library_f
Getting closer. Going to see if I can make changes and re-compile