diff --git a/mkdocs/config/base.py b/mkdocs/config/base.py
index a58f6621..cf14ebfb 100644
--- a/mkdocs/config/base.py
+++ b/mkdocs/config/base.py
@@ -64,6 +64,10 @@ class ValidationError(Exception):
     """Raised during the validation process of the config on errors."""
 
 
+PlainConfigSchemaItem = Tuple[str, BaseConfigOption]
+PlainConfigSchema = Sequence[PlainConfigSchemaItem]
+
+
 class Config(UserDict):
     """
     MkDocs Configuration dict
@@ -72,9 +76,7 @@ class Config(UserDict):
     for running validation on the structure and contents.
     """
 
-    def __init__(
-        self, schema: Sequence[Tuple[str, BaseConfigOption]], config_file_path: Optional[str] = None
-    ):
+    def __init__(self, schema: PlainConfigSchema, config_file_path: Optional[str] = None):
         """
         The schema is a Python dict which maps the config name to a validator.
         """
@@ -192,7 +194,7 @@ class Config(UserDict):
 
 
 @functools.lru_cache(maxsize=None)
-def get_schema(cls: type) -> Sequence[Tuple[str, BaseConfigOption]]:
+def get_schema(cls: type) -> PlainConfigSchema:
     """
     Extract ConfigOptions defined in a class (used just as a container) and put them into a schema tuple.
 
diff --git a/mkdocs/config/config_options.py b/mkdocs/config/config_options.py
index 82dbd51f..98e91353 100644
--- a/mkdocs/config/config_options.py
+++ b/mkdocs/config/config_options.py
@@ -8,7 +8,7 @@ from urllib.parse import urlsplit, urlunsplit
 import markdown
 
 from mkdocs import plugins, theme, utils
-from mkdocs.config.base import BaseConfigOption, Config, ValidationError
+from mkdocs.config.base import BaseConfigOption, Config, PlainConfigSchemaItem, ValidationError
 from mkdocs.exceptions import ConfigurationError
 
 
@@ -22,7 +22,7 @@ class SubConfig(BaseConfigOption):
     enable validation with `validate=True`.
     """
 
-    def __init__(self, *config_options, validate=False):
+    def __init__(self, *config_options: PlainConfigSchemaItem, validate=False):
         super().__init__()
         self.default = {}
         self.config_options = config_options
@@ -137,7 +137,7 @@ class ConfigItems(ListOfItems):
     options.
     """
 
-    def __init__(self, *config_options, required=False, validate=False):
+    def __init__(self, *config_options: PlainConfigSchemaItem, required=False, validate=False):
         super().__init__(SubConfig(*config_options, validate=validate))
         self.required = required
 
diff --git a/mkdocs/plugins.py b/mkdocs/plugins.py
index 1ebd0acc..cc8f5608 100644
--- a/mkdocs/plugins.py
+++ b/mkdocs/plugins.py
@@ -6,12 +6,12 @@ Implements the plugin API for MkDocs.
 
 import logging
 from collections import OrderedDict
-from typing import Any, Callable, Dict, Optional, Sequence, Tuple, TypeVar, overload
+from typing import Any, Callable, Dict, Optional, Tuple, TypeVar, overload
 
 import importlib_metadata
 import jinja2.environment
 
-from mkdocs.config.base import BaseConfigOption, Config
+from mkdocs.config.base import Config, PlainConfigSchema
 from mkdocs.livereload import LiveReloadServer
 from mkdocs.structure.files import Files
 from mkdocs.structure.nav import Navigation
@@ -43,7 +43,7 @@ class BasePlugin:
     All plugins should subclass this class.
     """
 
-    config_scheme: Sequence[Tuple[str, BaseConfigOption]] = ()
+    config_scheme: PlainConfigSchema = ()
     config: Config = {}  # type: ignore[assignment]
 
     def load_config(