This is my try to add EAN-13 support to the Barcode Generator Plugin for the Flipper Zero. Based on https://github.com/McAzzaMan/flipperzero-firmware/tree/UPC-A_Barcode_Generator/applications/barcode_generator
The Main issue is the backwards compatibblity to UPC-A ... Maybe I'll start over and write a EAN-13-only Barcode Generator first.
Put in your Flipper folder, in ...\flipper-firmware\applications\plugins\BarcodeGenerator13\
Compile in ..\flipper-firmware\
with the command ./fbt fap_Barcode_Generator13
(./ftb fap_[AppID from application.fam])
See also https://github.com/flipperdevices/flipperzero-firmware/blob/dev/documentation/fbt.md
Copy the created plugin to your Flipper Zero.