I don't think many use the B10
D variant as it has a poor performing/budget Broadcom chipset.
The favoured device for many kitizens was the higher syncing/more stable B10
A variant. It has 1 of Broadcom's flagship chipsets.
There might be a couple users though.
I am thinking about asking Zyxel for the source code for the VMG1312-B10D 5.13(AAXA.10)C0 release.
Good luck with that.
The last 3 requests I've made for source codes hasn't gone well.
The 1st I was told I needed to wait till the firmware had been released for 3 months, then the 2nd I was told 6 months.
Both of which I did and was provided the source code.
The last request I made was never fulfilled despite numerous attempts.
Before that they were great at providing the source code of their firmwares within a few days of request.
It's been a couple years since I've made any such request so perhaps they changed their ways.