This is a mysterious seal. Basic research indicates it is some form of ancient writing, intended on aiding one in banishing demons, efreet, followers of The Sightless One and other servants of the Outer Gods.
Rumors discuss how the magical heroes of this desert land were able to find and discover seals to make their weapons, armor and items more potent.
During a Long Rest, this seal can be fused with a piece of armor or a weapon. That piece of equipment becomes magical and gains a +1 enchantment bonus.