vpeter it is this one:
Amazon.com: 5 inch 800480 Resistive Touch Screen HDMI interface custom Raspbian LCD mini PC Supports Raspberry Pi 3 2 1 Model B B+ A+ & BeagleBone Black & Banana Pi / Banana Pro @XYG: Computers & Accessories
It shows up as "d-wav scientific co. ltd" in lsusb. dmesg also sees it "New USB device found, idVendor=0eef, idProduct=0005". A google search suggests it is a eGalax touchscreen.
Great news on the addon, I look forward to it!
Maybe I missed something but which touchscreen exactly are you using?
Btw: I send addon to libreelec repository and it will be available soon.