Maxim Popenker blogs about a modified Viet-Cong SVT-40 with some additional features:

While it looks very close to the original SVT-40 carbine, of which only a few thousand were made, it’s more probable that the gun was cut down to size from a full-size rifle. It is, however, consistent so far as I can determine with the SVT-40 carbine, so it’s possible it is a conversion of that very uncommon weapon.

The gun has been modified with a homemade folding stock, grip, and “chassis” to cover the open receiver which used to be housed inside the wood stock. The handguard has also been replaced with a two-piece unit, which looks like it might be sheet steel and either leather or wood.

Most significantly, though, the crafty person who made it has augmented the weapon with a Bren magazine. No word on whether the rifle still shoots its original caliber, and the magazine is modified to accept the wider 7.6x54R cartridges, or if the user has rechambered the gun for .303 British, which would involve setting the barrel back and reaming an entirely new chamber. Also possible is that the rifle is fed .303 British, while still being chambered for 7.62x54R. While these calibers should absolutely not be mixed, given the history of local “gunsmiths” mixing and matching calibers in this way, I would not discount it as a possibility.

Besides what’s evident in the picture, I have found no other details on the weapon, so if readers know anything else about it, please comment below.