user44795: I've been looking up OP_RETURN transactions on http://coinsecrets.org/ and I noticed that they all contain hashes that start with 6a, for instance:
6a28f7377a2065897e429287682bd2ed67ed7d0f5ebfc35cf4b1575756c3bebf0000b84002004b4d4400
Followed by their actual data: 
÷7z e~Bh+Òígí}^¿Ã\ô±WWVÃ¾¿¸@KMD
Is that hash the encoded data?
If not, what is it?

user24974: 6A is the hex representation of OP_RETURN:  https://en.bitcoin.it/wiki/Script
That is not a hash at all, but rather the raw encumbrance script.  You are looking at the code that actually contains the OP_RETURN.  You can decode these scripts here:  https://chainquery.com/bitcoin-api/decodescript

44795: <p>I've been looking up OP_RETURN transactions on <a href="http://coinsecrets.org/" rel="nofollow noreferrer">http://coinsecrets.org/</a> and I noticed that they all contain hashes that start with 6a, for instance:</p>

<p>6a28f7377a2065897e429287682bd2ed67ed7d0f5ebfc35cf4b1575756c3bebf0000b84002004b4d4400</p>

<p>Followed by their actual data: </p>

<p><a href="https://www.blocktrail.com/BTC/tx/aa931bf51d5afcae1abe7db4ccc26095838f6439ccf5901a741a6dd0c8c9b32e#tx_messages" rel="nofollow noreferrer">÷7z e~Bh+Òígí}^¿Ã\ô±WWVÃ¾¿¸@KMD</a></p>

<p>Is that hash the encoded data?
If not, what is it?</p>
 24974: <p><code>6A</code> is the hex representation of <code>OP_RETURN</code>:  <a href="https://en.bitcoin.it/wiki/Script" rel="nofollow noreferrer">https://en.bitcoin.it/wiki/Script</a></p>

<p>That is not a hash at all, but rather the raw encumbrance script.  You are looking at the code that actually contains the <code>OP_RETURN</code>.  You can decode these scripts here:  <a href="https://chainquery.com/bitcoin-api/decodescript" rel="nofollow noreferrer">https://chainquery.com/bitcoin-api/decodescript</a></p>
