It appears as though this emblem is in the game files, but not obtainable as of yet.
Tess, from Special Orders, will have it when it's available. If she has it, that probably means it's from an achievement or Grimoire completion. My guess would be something to do with completing hard-mode raids a certain amount of times or completing hard mode raids for each raid. We'll have to wait and see!
English
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Order a tricorn pin to get one as you can see my titan has it
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someone on my roster has it