Is there an example of a transaction that makes use of tx_extra field? Is this public unencrypted data?

Question

Is there a transaction that makes use of the tx_extra field that is viewable in the monero block explorer?

Answer 1

Is there an example of a transaction that makes use of tx_extra field? Is this public unencrypted data?

Every transaction makes use of tx extra as it places the tx public key in there. The data is public but can be encrypted (e.g. payment IDs are encrypted in extra).

...that is viewable in the monero block explorer?

Select a transaction in https://testnet.xmrchain.com or https://xmrchain.com and click "More Details" at the bottom, then "Show JSON representation of tx".

Answer 2

Using the example from this question's answer, and following jtgrassie's recommendation to use https://xmrchain.com with "More Details" -> "Show JSON representation of tx", the tx extra field can be found in here.

EDIT: better instructions

1. Go to https://xmrchain.com
2. Enter the transaction hash you want to look up, e.g. the example here
3. Go to bottom of page and click on "More Details"
4. Go to bottom of page again and click on "Show JSON representation of tx"
5. At bottom of page there is the entire transaction in JSON format. Tx_extra field is labeled "extra":
6. See this other question for details about the extra field.