As German authorities have discovered, the Halle shooter, Stephan Balliet, published a manifesto shortly before the attack, claiming that one of his objectives was to prove the viability of homemade guns, which he used during the attack.
The pictured communication may be indicative of this objective, with individuals associated with the far-right, especially in Germany and Europe, attempting to carry out copy-cat attacks in the coming weeks or months with homemade weapons.