user65332: While investigating some Bitcoin coinbase transactions, I notice that a lot of them have an output of the form
OP_RETURN OP_PUSHBYTES_36 b9e11b6d…
where ‘…’ is 32 bytes, probably a hash of something. I know coinbase outputs can be used for whatever the miner likes, so could be arbitrary. However, I do see a lot of examples starting with the exact same b9e11b6d four bytes. Merge mining is one possibility, but with some googling, I could not find examples using this format.
For example, I started by looking at block 733528. It has 3 op-return outputs. The first is for merge mining with RSK, the third is the Merkle root of the signature data (indicated by the 4 bytes aa21a9ed), and the second is the mystery one I am asking about.
The previous block 733527 also has this mystery output as its fourth op-return. The block before that does not have such an output, but the one before that does.
Even going back a few years to block 580000 (created 9 June 2019), I see outputs of this form.
Can someone identify what this is? Is it merge mining some other blockchain, or is there another purpose to these outputs?

user5406: The mentioned OP_RETURN output appears to be the footprint of merged-mining VCash, a Mimblewimble-based SHA-256d coin, with Bitcoin. I discovered this via the string 0xb9e11b6d appearing in these mining instructions.

65332: <p>While investigating some Bitcoin coinbase transactions, I notice that a lot of them have an output of the form</p>
<p><code>OP_RETURN OP_PUSHBYTES_36 b9e11b6d…</code></p>
<p>where ‘…’ is 32 bytes, probably a hash of something. I know coinbase outputs can be used for whatever the miner likes, so could be arbitrary. However, I do see a lot of examples starting with the exact same b9e11b6d four bytes. Merge mining is one possibility, but with some googling, I could not find examples using this format.</p>
<p>For example, I started by looking at block <a href="https://blockstream.info/tx/2a85992897c54db7baa8b474bdc03ce7867bd9d8f4b00329cedd223d9997b100?expand" rel="nofollow noreferrer">733528</a>. It has 3 op-return outputs. The first is for merge mining with RSK, the third is the Merkle root of the signature data (indicated by the 4 bytes aa21a9ed), and the second is the mystery one I am asking about.</p>
<p>The previous block <a href="https://blockstream.info/tx/9efb1979d187f25cca5baf7b264704382d057ce5b29514651b6248a43f47aad8?expand" rel="nofollow noreferrer">733527</a> also has this mystery output as its fourth op-return. The block before that does not have such an output, but the one before that does.</p>
<p>Even going back a few years to block <a href="https://blockstream.info/tx/9dc5b4ac6fe3d05cd4a76c472a529c8780c2d188f39b276328e403f105491724?expand" rel="nofollow noreferrer">580000</a> (created 9 June 2019), I see outputs of this form.</p>
<p>Can someone identify what this is? Is it merge mining some other blockchain, or is there another purpose to these outputs?</p>
 5406: <p>The mentioned <code>OP_RETURN</code> output appears to be the footprint of merged-mining <em><a href="https://bitcointalk.org/index.php?topic=5129919.0" rel="nofollow noreferrer">VCash</a></em>, a Mimblewimble-based SHA-256d coin, with Bitcoin. I discovered this via the string <code>0xb9e11b6d</code> appearing in these <a href="https://github.com/vcashorg/vcash/blob/vcash/doc/pool_merge_mining.md#what-do-you-need-to-do" rel="nofollow noreferrer">mining instructions</a>.</p>
