Add previousOwner field to transfer response

[janniks]

In a paginated API it would be a nice-to-have to get the previousOwner / sender in the transfer response.

The information exists and can be fetched, but especially in pagination it can be annoying for the developer.

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• To any non-genesis transfer event, add a sender (or previousAddress) field, which simply stores the "owner" before the transfer in the transfer event

[chresko]

What's the current process for fetching this information?

[janniks]

Currently not shown, would need API changes

[rafaelcr]

We'll probably need to implement a change in hord first before the API so it can send us previous addresses, because if we calculate these API side and we ever get a gap in inscription transfers we would be showing incorrect information

[smcclellan]

As we have fewer gaps, decreasing priority.