What does the hash symbol mean in OpenAPI / Swagger specification paths?

I see '/{Bucket}/{Key}#x-amz-copy-source': in the yaml file for example. I see this in the parameters listed for a particular request, which might be correlated? (I couldn't find any docs on it):

- name: x-amz-copy-source
  in: header
  required: true
  description: '<p>Specifies the source object for the copy operation. You specify the value in one of two formats, depending on whether you want to access the source object through an <a href="https://docs.aws.amazon.com/AmazonS3/latest/userguide/access-points.html">access point</a>:</p> <ul> <li> <p>For objects not accessed through an access point, specify the name of the source bucket and the key of the source object, separated by a slash (/). For example, to copy the object <code>reports/january.pdf</code> from the bucket <code>awsexamplebucket</code>, use <code>awsexamplebucket/reports/january.pdf</code>. The value must be URL encoded.</p> </li> <li> <p>For objects accessed through access points, specify the Amazon Resource Name (ARN) of the object as accessed through the access point, in the format <code>arn:aws:s3:&lt;Region&gt;:&lt;account-id&gt;:accesspoint/&lt;access-point-name&gt;/object/&lt;key&gt;</code>. For example, to copy the object <code>reports/january.pdf</code> through access point <code>my-access-point</code> owned by account <code>123456789012</code> in Region <code>us-west-2</code>, use the URL encoding of <code>arn:aws:s3:us-west-2:123456789012:accesspoint/my-access-point/object/reports/january.pdf</code>. The value must be URL encoded.</p> <note> <p>Amazon S3 supports copy operations using access points only when the source and destination buckets are in the same Amazon Web Services Region.</p> </note> <p>Alternatively, for objects accessed through Amazon S3 on Outposts, specify the ARN of the object as accessed in the format <code>arn:aws:s3-outposts:&lt;Region&gt;:&lt;account-id&gt;:outpost/&lt;outpost-id&gt;/object/&lt;key&gt;</code>. For example, to copy the object <code>reports/january.pdf</code> through outpost <code>my-outpost</code> owned by account <code>123456789012</code> in Region <code>us-west-2</code>, use the URL encoding of <code>arn:aws:s3-outposts:us-west-2:123456789012:outpost/my-outpost/object/reports/january.pdf</code>. The value must be URL encoded. </p> </li> </ul> <p>To copy a specific version of an object, append <code>?versionId=&lt;version-id&gt;</code> to the value (for example, <code>awsexamplebucket/reports/january.pdf?versionId=QUpfdndhfd8438MNFDN93jdnJFkdmqnh893</code>). If you don''t specify a version ID, Amazon S3 copies the latest version of the source object.</p>'
  schema:
    type: string
    pattern: \/.+\/.+

While the hash # is in the path, this parameter says in: header. What does the hash "parameter" mean in this case?

There are more, such as '/{Bucket}/{Key}#uploads'. Here, it is for a query parameter:

- name: uploads
  in: query
  required: true
  schema:
    type: boolean
    enum:
      - true
  allowEmptyValue: true

I don't think it means it's required, because there is a required attribute. Any help would be appreciated.

In another case we seem to have 2:

'/{Bucket}#analytics&id'