diff --git a/src/flake8/options/config.py b/src/flake8/options/config.py
index 9325495..468341b 100644
--- a/src/flake8/options/config.py
+++ b/src/flake8/options/config.py
@@ -15,8 +15,6 @@ __all__ = ("ConfigFileFinder", "MergedConfigParser")
 class ConfigFileFinder(object):
     """Encapsulate the logic for finding and reading config files."""
 
-    PROJECT_FILENAMES = ("setup.cfg", "tox.ini")
-
     def __init__(self, program_name, args, extra_config_files):
         """Initialize object to find config files.