This proposal aims to register Tether USD from AssetHub (Polkadot native) on Zeitgeist.

Schedule a majority-carries referendum to be tabled next once it is legal to schedule
an external referendum.

The dispatch of this call must be `ExternalMajorityOrigin`.

- `proposal_hash`: The preimage hash of the proposal.

Unlike `external_propose`, blacklisting has no effect on this and it may replace a
pre-scheduled `external_propose` call.

Weight: `O(1)`

- **Problem Statement:** Lack of Tether USD registration on Zeitgeist for AssetHub users.
- **Significance:** Enhances usability for AssetHub users and expands the range of assets available on Zeitgeist.
- **Proposed Solution:** Register Tether USD from AssetHub on Zeitgeist.
- **Expected Outcomes:** Increased usability and asset diversity on Zeitgeist for AssetHub users.

#51 Register Tether USD (Polkadot AssetHub)

No Active Proposals