From e229022d44c4cf4fa063ecf6d00c2a9182456afa Mon Sep 17 00:00:00 2001
From: WhoSoup <34172041+WhoSoup@users.noreply.github.com>
Date: Mon, 29 Jun 2020 16:18:58 +0200
Subject: [PATCH] Minor clarification

It is currently possible to add zero-length ExtIDs and both the factom client and factomd handle them fine.

Example: https://explorer.factom.pro/chains/98133e8546d2ced588807803795b1bad5d7cfa2faa0371bfcf5e560ccf5add29
This entry has three ExtIDs that are zero length. Raw data: `0098133e8546d2ced588807803795b1bad5d7cfa2faa0371bfcf5e560ccf5add2900090000000000000001de224e657720636861696e2e22`

```
          Version: 00
         Chain ID: 98133e8546d2ced588807803795b1bad5d7cfa2faa0371bfcf5e560ccf5add29
      ExtID Bytes: 0009
Length of ExtID 1: 0000
Length of ExtID 2: 0000
Length of ExtID 3: 0000
Length of ExtID 4: 0001
  Data of ExtID 4: de
          Content: 224e657720636861696e2e22
```
---
 factomDataStructureDetails.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/factomDataStructureDetails.md b/factomDataStructureDetails.md
index 085551b..7752bf1 100644
--- a/factomDataStructureDetails.md
+++ b/factomDataStructureDetails.md
@@ -52,7 +52,7 @@ External IDs and Content is not checked for validity, or sanitized, as it is onl
 | 2 bytes | ExtIDs Size | Describes how many bytes required for the set of External IDs for this Entry.  Must be less than or equal to the Payload size.  Big endian. |
 | **Payload** | | This is the data between the end of the Header and the end of the Content. |
 | **External IDs** |  | This section is only interpreted and enforced if the External ID Size is greater than zero. |
-| 2 bytes | ExtID element 0 length | This is the number of the following bytes to be interpreted as an External ID element.  Cannot be 0 length. |
+| 2 bytes | ExtID element 0 length | This is the number of the following bytes to be interpreted as an External ID element.  Can be 0 length. |
 | variable | ExtID 0 | This is the data for the first External ID. |
 | 2 bytes | ExtID X | Size of the X External ID  |
 | variable | ExtID X data | This is the Xth element.  The last byte of the last element must fall on the last byte specified ExtIDs Size in the header. |