1 files changed, 5 insertions, 0 deletions
diff --git a/sphinx/errors.py b/sphinx/errors.py
index 7f8b1fbd5..64036721f 100644
--- a/sphinx/errors.py
+++ b/sphinx/errors.py
@@ -126,3 +126,8 @@ class PycodeError(Exception):
 class NoUri(Exception):
     """Raised by builder.get_relative_uri() if there is no URI available."""
     pass
+
+
+class FiletypeNotFoundError(Exception):
+    "Raised by get_filetype() if a filename matches no source suffix."
+    pass