diff --git a/worlds/Files.py b/worlds/Files.py
index 6fee582c872..6e9bf6b31b5 100644
--- a/worlds/Files.py
+++ b/worlds/Files.py
@@ -7,7 +7,7 @@
 import os
 import threading
 
-from typing import ClassVar, Dict, List, Literal, Tuple, Any, Optional, Union, BinaryIO, overload
+from typing import ClassVar, Dict, List, Literal, Tuple, Any, Optional, Union, BinaryIO, overload, Sequence
 
 import bsdiff4
 
@@ -41,7 +41,7 @@ def get_handler(file: str) -> Optional[AutoPatchRegister]:
 
 class AutoPatchExtensionRegister(abc.ABCMeta):
     extension_types: ClassVar[Dict[str, AutoPatchExtensionRegister]] = {}
-    required_extensions: List[str] = []
+    required_extensions: Tuple[str, ...] = ()
 
     def __new__(mcs, name: str, bases: Tuple[type, ...], dct: Dict[str, Any]) -> AutoPatchExtensionRegister:
         # construct class
@@ -51,7 +51,9 @@ def __new__(mcs, name: str, bases: Tuple[type, ...], dct: Dict[str, Any]) -> Aut
         return new_class
 
     @staticmethod
-    def get_handler(game: str) -> Union[AutoPatchExtensionRegister, List[AutoPatchExtensionRegister]]:
+    def get_handler(game: Optional[str]) -> Union[AutoPatchExtensionRegister, List[AutoPatchExtensionRegister]]:
+        if not game:
+            return APPatchExtension
         handler = AutoPatchExtensionRegister.extension_types.get(game, APPatchExtension)
         if handler.required_extensions:
             handlers = [handler]
@@ -191,7 +193,7 @@ class APProcedurePatch(APAutoPatchInterface):
     hash: Optional[str]  # base checksum of source file
     source_data: bytes
     patch_file_ending: str = ""
-    files: Dict[str, bytes] = {}
+    files: Dict[str, bytes]
 
     @classmethod
     def get_source_data(cls) -> bytes:
@@ -206,6 +208,7 @@ def get_source_data_with_cache(cls) -> bytes:
 
     def __init__(self, *args: Any, **kwargs: Any):
         super(APProcedurePatch, self).__init__(*args, **kwargs)
+        self.files = {}
 
     def get_manifest(self) -> Dict[str, Any]:
         manifest = super(APProcedurePatch, self).get_manifest()
@@ -277,7 +280,7 @@ def __init__(self, *args: Any, patched_path: str = "", **kwargs: Any) -> None:
         super(APDeltaPatch, self).__init__(*args, **kwargs)
         self.patched_path = patched_path
 
-    def write_contents(self, opened_zipfile: zipfile.ZipFile):
+    def write_contents(self, opened_zipfile: zipfile.ZipFile) -> None:
         self.write_file("delta.bsdiff4",
                         bsdiff4.diff(self.get_source_data_with_cache(), open(self.patched_path, "rb").read()))
         super(APDeltaPatch, self).write_contents(opened_zipfile)
@@ -296,12 +299,12 @@ class APTokenMixin:
     """
     A class that defines functions for generating a token binary, for use in patches.
     """
-    tokens: List[
+    _tokens: Sequence[
         Tuple[APTokenTypes, int, Union[
             bytes,  # WRITE
             Tuple[int, int],  # COPY, RLE
             int  # AND_8, OR_8, XOR_8
-        ]]] = []
+        ]]] = ()
 
     def get_token_binary(self) -> bytes:
         """
@@ -309,8 +312,8 @@ def get_token_binary(self) -> bytes:
         :return: A bytes object representing the token data.
         """
         data = bytearray()
-        data.extend(len(self.tokens).to_bytes(4, "little"))
-        for token_type, offset, args in self.tokens:
+        data.extend(len(self._tokens).to_bytes(4, "little"))
+        for token_type, offset, args in self._tokens:
             data.append(token_type)
             data.extend(offset.to_bytes(4, "little"))
             if token_type in [APTokenTypes.AND_8, APTokenTypes.OR_8, APTokenTypes.XOR_8]:
@@ -351,11 +354,14 @@ def write_token(self,
                     data: bytes) -> None:
         ...
 
-    def write_token(self, token_type: APTokenTypes, offset: int, data: Union[bytes, Tuple[int, int], int]):
+    def write_token(self, token_type: APTokenTypes, offset: int, data: Union[bytes, Tuple[int, int], int]) -> None:
         """
         Stores a token to be used by patching.
         """
-        self.tokens.append((token_type, offset, data))
+        if not isinstance(self._tokens, list):
+            assert len(self._tokens) == 0, f"{type(self)}._tokens was tampered with."
+            self._tokens = []
+        self._tokens.append((token_type, offset, data))
 
 
 class APPatchExtension(metaclass=AutoPatchExtensionRegister):
@@ -371,10 +377,10 @@ class APPatchExtension(metaclass=AutoPatchExtensionRegister):
     Patch extension functions must return the changed bytes.
     """
     game: str
-    required_extensions: List[str] = []
+    required_extensions: ClassVar[Tuple[str, ...]] = ()
 
     @staticmethod
-    def apply_bsdiff4(caller: APProcedurePatch, rom: bytes, patch: str):
+    def apply_bsdiff4(caller: APProcedurePatch, rom: bytes, patch: str) -> bytes:
         """Applies the given bsdiff4 from the patch onto the current file."""
         return bsdiff4.patch(rom, caller.get_file(patch))
 
@@ -411,7 +417,7 @@ def apply_tokens(caller: APProcedurePatch, rom: bytes, token_file: str) -> bytes
         return bytes(rom_data)
 
     @staticmethod
-    def calc_snes_crc(caller: APProcedurePatch, rom: bytes):
+    def calc_snes_crc(caller: APProcedurePatch, rom: bytes) -> bytes:
         """Calculates and applies a valid CRC for the SNES rom header."""
         rom_data = bytearray(rom)
         if len(rom) < 0x8000: