Remove subevent.items and subevent.variations as they very much not do what you'd expect

src/pretix/base/models/event.py

@@ -1468,8 +1468,6 @@ class SubEvent(EventMixin, LoggedModel):
     seating_plan = models.ForeignKey('SeatingPlan', on_delete=models.PROTECT, null=True, blank=True,
                                      related_name='subevents', verbose_name=_('Seating plan'))
 
-    items = models.ManyToManyField('Item', through='SubEventItem')
-    variations = models.ManyToManyField('ItemVariation', through='SubEventItemVariation')
     comment = models.TextField(
         verbose_name=_("Internal comment"),
         null=True, blank=True

src/tests/api/test_subevents.py

@@ -28,7 +28,7 @@ from django_countries.fields import Country
 from django_scopes import scopes_disabled
 
 from pretix.base.models import (
-    InvoiceAddress, Order, OrderPosition, SeatingPlan, SubEvent,
+    InvoiceAddress, ItemVariation, Order, OrderPosition, SeatingPlan, SubEvent,
 )
 from pretix.base.models.orders import OrderFee
 
@@ -503,7 +503,7 @@ def test_subevent_update(token_client, organizer, event, subevent, item, item2,
     )
     assert resp.status_code == 200
     with scopes_disabled():
-        assert subevent.items.get(id=item.pk).default_price == Decimal('23.00')
+        assert event.items.get(id=item.pk).default_price == Decimal('23.00')
     assert subevent.item_price_overrides[item.pk] == Decimal('99.99')
 
     resp = token_client.patch(
@@ -609,7 +609,7 @@ def test_subevent_update(token_client, organizer, event, subevent, item, item2,
     )
     assert resp.status_code == 200
     with scopes_disabled():
-        assert subevent.variations.get(id=variations[0].pk).default_price == Decimal('12.00')
+        assert ItemVariation.objects.get(id=variations[0].pk).default_price == Decimal('12.00')
         assert subevent.var_price_overrides[variations[0].pk] == Decimal('99.99')
 
     resp = token_client.patch(