diff --git a/app/entities/instance-metadata/page.mdx b/app/entities/instance-metadata/page.mdx
index 0c10a0b..af52fd5 100644
--- a/app/entities/instance-metadata/page.mdx
+++ b/app/entities/instance-metadata/page.mdx
@@ -9,7 +9,9 @@ Contains metadata about a Versia instance, such as capabilities and endpoints. {
 
 ## The `null` Author
 
-On all entities that have an `author` field, the `author` can be `null` to represent the instance itself as the author (like ActivityPub's Server Actors). In this case, the instance's public key should be used to verify the entity. To know which instance's public key to use, the entity signature should be used.
+On some entities that have an `author` field, the `author` can be `null` to represent the instance itself as the author (like ActivityPub's Server Actors). In this case, the instance's public key should be used to verify the entity. To know which instance's public key to use, the entity signature should be used.
+
+Check the entity's documentation page to see if it supports this (it will be noted in the `author` field).
 
 ## Entity Definition
 
diff --git a/app/signatures/page.mdx b/app/signatures/page.mdx
index 5687b2b..9121c57 100644
--- a/app/signatures/page.mdx
+++ b/app/signatures/page.mdx
@@ -155,4 +155,4 @@ const isVerified = await crypto.subtle.verify(
 if (!isVerified) {
     return new Response("Signature verification failed", { status: 401 });
 }
-```
\ No newline at end of file
+```