Updates from Andriy's feedback

entity-framework/core/modeling/relationships.md

@@ -190,7 +190,7 @@ Relationships defined in the model can be used in various ways. For example:
   - [Eagerly](xref:core/querying/related-data/eager) as part of a LINQ query, using `Include`.
   - [Lazily](xref:core/querying/related-data/lazy) using lazy-loading proxies, or lazy-loading without proxies.
   - [Explicitly](xref:core/querying/related-data/explicit) using the `Load` or `LoadAsync` methods.
-- Relationships can be used in [data seeding](xref:core/modeling/data-seeding).
+- Relationships can be used in [data seeding](xref:core/modeling/data-seeding) through matching of PK values to FK values.
 - Relationships can be used to [track graphs of entities](xref:core/change-tracking/index). Relationships are then used by the change tracker to:
   - [Detect changes in relationships and perform fixup](xref:core/change-tracking/relationship-changes)
   - [Send foreign key updates to the database](xref:core/saving/related-data) with `SaveChanges` or `SaveChangesAsync`

entity-framework/core/modeling/relationships/conventions.md

@@ -190,6 +190,7 @@ Once the navigations for a relationship have either been discovered or configure
   - `<navigation property name>Id`
   - `<principal entity type name><principal key property name>`
   - `<principal entity type name>Id`
+- In addition, if the dependent end has been explicitly configured using the model building API, and the dependent primary key is compatible, then the dependent primary key will also be used as the foreign key.
 
 > [!TIP]
 > The "Id" suffix can have any casing.
@@ -297,7 +298,7 @@ If EF has determined the dependent end of the relationship but no foreign key pr
 
 ## Cascade delete
 
-By convention, non-nullable foreign key properties are configured to [cascade delete](xref:core/saving/cascade-delete). Nullable foreign key properties are configured to not cascade delete.
+By convention, required relationships are configured to [cascade delete](xref:core/saving/cascade-delete). Optional relationships are configured to not cascade delete.
 
 ## Many-to-many
 
@@ -428,6 +429,9 @@ For composite foreign keys, an index is created covering all the foreign key col
 CREATE INDEX "IX_Post_ContainingBlogId1_ContainingBlogId2" ON "Post" ("ContainingBlogId1", "ContainingBlogId2");
 ```
 
+> [!NOTE]
+> EF does not create indexes for properties that are already covered by an existing index or primary key constraint.
+
 ### How to stop EF creating indexes for foreign keys
 
 Indexes have overhead, and, [as asked here](https://github.com/dotnet/efcore/issues/10855), it may not always be appropriate to create them for all FK columns. To achieve this, the `ForeignKeyIndexConvention` can be removed when building the model:

entity-framework/core/modeling/relationships/foreign-and-principal-keys.md

@@ -198,7 +198,7 @@ By convention, EF creates a database index for the property or properties of a f
 
 ## Principal keys
 
-By convention, foreign keys are constrained to the primary key at the principal end of the relationship. However, an alternate key can be used instead. This is achieved using `HasPrincipalKey` on the model building API. For Example, for a single property foreign key:
+By convention, foreign keys are constrained to the primary key at the principal end of the relationship. However, an alternate key can be used instead. This is achieved using `HasPrincipalKey` on the model building API. For example, for a single property foreign key:
 
 <!--
             protected override void OnModelCreating(ModelBuilder modelBuilder)