diff --git a/slack_sdk/models/blocks/block_elements.py b/slack_sdk/models/blocks/block_elements.py
index be683162..85a9742e 100644
--- a/slack_sdk/models/blocks/block_elements.py
+++ b/slack_sdk/models/blocks/block_elements.py
@@ -1668,7 +1668,6 @@ def attributes(self) -> Set[str]:  # type: ignore[override]
             {
                 "url",
                 "text",
-                "icon_url",
             }
         )
 
@@ -1677,7 +1676,6 @@ def __init__(
         *,
         url: str,
         text: str,
-        icon_url: Optional[str] = None,
         **others: Dict,
     ):
         """
@@ -1687,13 +1685,11 @@ def __init__(
         Args:
             url (required): The URL type source.
             text (required): Display text for the URL.
-            icon_url: Optional icon URL to display with the source.
         """
         super().__init__(type=self.type)
         show_unknown_key_warning(self, others)
         self.url = url
         self.text = text
-        self.icon_url = icon_url
 
 
 # -------------------------------------------------
diff --git a/slack_sdk/web/chat_stream.py b/slack_sdk/web/chat_stream.py
index 580f7cac..575aed8c 100644
--- a/slack_sdk/web/chat_stream.py
+++ b/slack_sdk/web/chat_stream.py
@@ -196,17 +196,17 @@ def stop(
 
     def _flush_buffer(self, chunks: Optional[Sequence[Union[Dict, Chunk]]] = None, **kwargs) -> SlackResponse:
         """Flush the internal buffer with chunks by making appropriate API calls."""
-        flushings: List[Union[Dict, Chunk]] = []
+        chunks_to_flush: List[Union[Dict, Chunk]] = []
         if len(self._buffer) != 0:
-            flushings.append(MarkdownTextChunk(text=self._buffer))
+            chunks_to_flush.append(MarkdownTextChunk(text=self._buffer))
         if chunks is not None:
-            flushings.extend(chunks)
+            chunks_to_flush.extend(chunks)
         if not self._stream_ts:
             response = self._client.chat_startStream(
                 **self._stream_args,
                 token=self._token,
                 **kwargs,
-                chunks=flushings,
+                chunks=chunks_to_flush,
             )
             self._stream_ts = response.get("ts")
             self._state = "in_progress"
@@ -216,7 +216,7 @@ def _flush_buffer(self, chunks: Optional[Sequence[Union[Dict, Chunk]]] = None, *
                 channel=self._stream_args["channel"],
                 ts=self._stream_ts,
                 **kwargs,
-                chunks=flushings,
+                chunks=chunks_to_flush,
             )
         self._buffer = ""
         return response
diff --git a/tests/slack_sdk/models/test_chunks.py b/tests/slack_sdk/models/test_chunks.py
index 293f5acb..78845b30 100644
--- a/tests/slack_sdk/models/test_chunks.py
+++ b/tests/slack_sdk/models/test_chunks.py
@@ -66,7 +66,6 @@ def test_json(self):
                     UrlSourceElement(
                         text="The Free Encyclopedia",
                         url="https://wikipedia.org",
-                        icon_url="https://example.com/globe.png",
                     ),
                 ],
             ).to_dict(),
@@ -86,7 +85,6 @@ def test_json(self):
                         "type": "url",
                         "text": "The Free Encyclopedia",
                         "url": "https://wikipedia.org",
-                        "icon_url": "https://example.com/globe.png",
                     },
                 ],
             },