The revolutionary survivalist "Surviestaloff" Telegram channel introduces itself as dealing with "urban survival, preparation, civil war." As of December 23, 2021, the channel has 351 subscribers. It has shared 208 videos and 15 audio files. The channel operator could be a member of the ultra "Milice Rouge" group, as a pinned post shows a France Info news outlet item picturing a French flag with the words "Milice Rouge" ("red militia") and the comment by the channel operator: "[…] we are on France Info […]" 
On December 21, "Surviestaloff" shared two videos demonstrating how to make and use a weapon. 
In the first video, the channel administrator explains how to make the weapon and how to use it in a "war." He says: "You asked many times for a tutorial on this stuff. It costs €2.50. You need two handles – broken drill handles or whatever handles you got, two PVC tubes. At the bottom end you place something made of metal in order to prevent your mortar from going to the other side - and it's perfect, it works. You can use it legally for your own pleasure during the New Year. Or you can use it for something else. You know what I mean. When our enemies use these weapons, they use them without a launcher. They don't know how to use them. You have to think about how to use their weapons in time of war with the same capacity, the same technology, but not with the same intelligence [as your stupid enemies]. We can produce dozens, twenty, fifty of these, in metal, with improved ammunition..." The subsequent video appears to demonstrate the weapon being used with a launcher.
On December 22, the channel shared a photo of a balaclava-wearing man in the street at night, holding what seems to be the weapon built on the video, in firing position.