Hello! I assume https://github.com/lxde/lxterminal is the upstream git repo and it looks to me like it's been ported to the new vte long ago, see also: https://sourceforge.net/p/lxde/patches/493/
Could you please consider investigating if shipping a git snapshot of the software as the debian package is suitable (or ask your upstream to cut a release and package that)? If a snapshot is not suitable, please tell us what the blockers are and if there's anything we can help out with. Regards, Andreas Henriksson
