diff --git a/src/calibre/customize/__init__.py b/src/calibre/customize/__init__.py
index 8f8c6ccf9c..3da9230dff 100644
--- a/src/calibre/customize/__init__.py
+++ b/src/calibre/customize/__init__.py
@@ -334,9 +334,8 @@ class FileTypePlugin(Plugin):  # {{{
     #: methods of the plugin are called.
     on_postimport  = False
 
-    #: If True, this plugin is run after a book file is added
-    #: to the database. In this case the postconvert method of
-    #: the plugin is called.
+    #: If True, this plugin is run after a book is converted.
+    #: In this case the postconvert method of the plugin is called.
     on_postconvert = False
 
     #: If True, this plugin is run after a book file is deleted
@@ -390,8 +389,8 @@ class FileTypePlugin(Plugin):  # {{{
 
     def postconvert(self, book_id, book_format, db):
         '''
-        Called post conversion, i.e., after the book file has been added to the database. Note that
-        it is run after a conversion only, not after a book is added. It is useful for modifying
+        Called post conversion, i.e., after the conversion output book file has been added to the database.
+        Note that it is run after a conversion only, not after a book is added. It is useful for modifying
         the book record based on the contents of the newly added file.
 
         :param book_id: Database id of the added book.
diff --git a/src/calibre/customize/ui.py b/src/calibre/customize/ui.py
index c4f6d1995b..57d064f8f4 100644
--- a/src/calibre/customize/ui.py
+++ b/src/calibre/customize/ui.py
@@ -210,9 +210,8 @@ def run_plugins_on_postimport(db, book_id, fmt):
         with plugin:
             try:
                 plugin.postimport(book_id, fmt, db)
-            except:
-                print('Running file type plugin %s failed with traceback:'%
-                       plugin.name)
+            except Exception:
+                print(f'Running file type plugin {plugin.name} failed with traceback:', file=sys.stderr)
                 traceback.print_exc()
 
 
@@ -224,9 +223,8 @@ def run_plugins_on_postconvert(db, book_id, fmt):
         with plugin:
             try:
                 plugin.postconvert(book_id, fmt, db)
-            except:
-                print('Running file type plugin %s failed with traceback:'%
-                       plugin.name)
+            except Exception:
+                print(f'Running file type plugin {plugin.name} failed with traceback:', file=sys.stderr)
                 traceback.print_exc()
 
 
@@ -238,9 +236,8 @@ def run_plugins_on_postdelete(db, book_id, fmt):
         with plugin:
             try:
                 plugin.postdelete(book_id, fmt, db)
-            except:
-                print('Running file type plugin %s failed with traceback:'%
-                       plugin.name)
+            except Exception:
+                print(f'Running file type plugin {plugin.name} failed with traceback:', file=sys.stderr)
                 traceback.print_exc()
 
 
@@ -254,8 +251,7 @@ def run_plugins_on_postadd(db, book_id, fmt_map):
             try:
                 plugin.postadd(book_id, fmt_map, db)
             except Exception:
-                print('Running file type plugin %s failed with traceback:'%
-                       plugin.name)
+                print(f'Running file type plugin {plugin.name} failed with traceback:', file=sys.stderr)
                 traceback.print_exc()
 
 # }}}