List destinations reachable from a Link-account source

Response for GET /api/link/v1/enterprises/{enterpriseId}/transfer-destinations.

Given a Link-account source, returns the destinations it can transfer to.

Segments:

• internalDestinations — off-chain reachable accounts (same-venue), grouped by account with subtype entries. May be empty when no same-venue rail qualifies.
• externalDestinations — on-chain reachable accounts. May be cross-venue or same- venue but in a different account hierarchy from the source. Same-hierarchy entries are suppressed since they're already covered by the internal segment.

sourceSupportsOnChainWithdrawal indicates whether BitGo wallet / external-address destinations can also be used alongside the Link-account destinations returned here. It is a property of the source venue, not of the caller's permission scope — always present, even when the caller's link.account.view scope yields no Link-account rows.

Not paginated — the candidate set (enterprise Link accounts at a small number of candidate venues) is bounded and returned in full in one response.