[bot]update openapi3 schema

Author: github-actions[bot]

api/build/core-openapi3.yaml

@@ -87,7 +87,8 @@ paths:
             The data is a gzipped tarball (.tar.gz) named `[email protected]`, where
             - `export[numbers]` is the word `export` with 20 random digits appended to it
             - `user` is the actors' name
-            - `subdomain.example.com` is the FQDN of the server the actor is 
+            - `subdomain.example.com` is the FQDN of the server the actor is registered on.
+
             This file archive contains a file `messages.json` which is a JSON `MessageBatch` of all
             messages sent by the user. Note the [definition of the word "message" in polyproto](https://docs.polyphony.chat/Protocol%20Specifications/core/#:~:text=software%20for%20clients.-,message%2C%20messages,-%3A%20In%20the%20context).
             If the server where the data export was requested from has [RawR](https://docs.polyphony.chat/Protocol%20Specifications/core/#731-resource-addressing-with-relative-roots)
@@ -112,7 +113,8 @@ paths:
             The data is a gzipped tarball (.tar.gz) named `[email protected]`, where
             - `export[numbers]` is the word `export` with 20 random digits appended to it
             - `user` is the actors' name
-            - `subdomain.example.com` is the FQDN of the server the actor is 
+            - `subdomain.example.com` is the FQDN of the server the actor is registered on.
+
             This file archive contains a file `messages.json` which is a JSON `MessageBatch` of all
             messages sent by the user. Note the [definition of the word "message" in polyproto](https://docs.polyphony.chat/Protocol%20Specifications/core/#:~:text=software%20for%20clients.-,message%2C%20messages,-%3A%20In%20the%20context).
             If the server where the data export was requested from has [RawR](https://docs.polyphony.chat/Protocol%20Specifications/core/#731-resource-addressing-with-relative-roots)
@@ -137,7 +139,8 @@ paths:
             The data is a gzipped tarball (.tar.gz) named `[email protected]`, where
             - `export[numbers]` is the word `export` with 20 random digits appended to it
             - `user` is the actors' name
-            - `subdomain.example.com` is the FQDN of the server the actor is 
+            - `subdomain.example.com` is the FQDN of the server the actor is registered on.
+
             This file archive contains a file `messages.json` which is a JSON `MessageBatch` of all
             messages sent by the user. Note the [definition of the word "message" in polyproto](https://docs.polyphony.chat/Protocol%20Specifications/core/#:~:text=software%20for%20clients.-,message%2C%20messages,-%3A%20In%20the%20context).
             If the server where the data export was requested from has [RawR](https://docs.polyphony.chat/Protocol%20Specifications/core/#731-resource-addressing-with-relative-roots)