diff --git a/tuf/api/exceptions.py b/tuf/api/exceptions.py
index 1d4081af..9a1303bc 100644
--- a/tuf/api/exceptions.py
+++ b/tuf/api/exceptions.py
@@ -12,7 +12,9 @@
 
 
 class RepositoryError(Exception):
-    """An error with a repository's state, such as a missing file."""
+    """An error with a repository's state, such as a missing file.
+    It covers all exceptions that come from the repository side when
+    looking from the perspective of users of metadata API or ngclient."""
 
 
 class UnsignedMetadataError(RepositoryError):