Further explain 'rest'.

barneygale · barneygale · commit 77712d2fccd8 · 2024-04-02T00:13:41.000+01:00
diff --git a/Lib/posixpath.py b/Lib/posixpath.py
@@ -423,7 +423,10 @@ def realpath(filename, *, strict=False):
         pardir = '..'
         getcwd = os.getcwd
 
-    # The stack of unresolved path parts.
+    # The stack of unresolved path parts. When popped, a special value of None
+    # indicates that a symlink target has been resolved, and that the original
+    # symlink path can be retrieved by popping again. The [::-1] slice is a
+    # very fast way of spelling list(reversed(...)).
     rest = filename.split(sep)[::-1]
 
     # The resolved path, which is absolute throughout this function.
