[FILE][TemporaryFile] Fix various issues now that we also have Symfony's file abstractions

docs/developer/src/SUMMARY.md

@@ -2,6 +2,7 @@
 
 - [Architecture: Modules](./architecture.md)
     - [Programming Style](./paradigms.md)
+    - [Exceptions](./exceptions.md)
     - [Events](./events.md)
     - [Database](./database.md)
     - [Cache](./cache.md)
@@ -33,4 +34,5 @@
     - [Queues](./core/queues.md)
     - [Files](./core/files.md)
     - [Security](./core/security.md)
-    - [HTTP Client](./core/http.md)
+    - [HTTP Client](./core/http.md)
+    - [Exception handling](./core/exception_handler.md)

docs/developer/src/architecture.md

@@ -12,10 +12,11 @@ which is elaborated in [Database](./database.md);
 - [Routes and Controllers](./routes_and_controllers.md);
 - [Templates](./templates.md);
 - [Internationalization (i18n)](https://en.wikipedia.org/wiki/Internationalization_and_localization), elaborated in [Internationalization](internationalization.md);
+- [Exceptions](./exceptions.md);
 - [Log](./log.md);
 - [Queues](./queues.md);
 - [Files](./files.md);
-- [Security](./security.md);
+- [Sessions and Security](./sessions_and_security.md);
 - [HTTP Client](./http.md).
 
 Everything else uses most of this.
@@ -48,6 +49,13 @@ Currently, GNU social has the following components:
 - Avatar
 - Posting
 
+#### Design principles
+
+- Components are independent so do not interfere with each other;
+- Component implementations are hidden;
+- Communication is through well-defined events and interfaces (for models);
+- One component can be replaced by another if its events are maintained.
+
 ### Plugins (Unix Tools Design Philosophy)
 
 GNU social is true to the Unix-philosophy of small programs to do a small job.

docs/developer/src/core.md

@@ -14,5 +14,5 @@ The `core` tries to be minimal. The essence of it being various wrappers around
 - [Utils](./core/util.md);
 - [Queues](./core/queues.md);
 - [Files](./core/files.md);
-- [Security](./core/security.md);
+- [Sessions and Security](./core/security.md);
 - [HTTP Client](./core/http.md).

docs/developer/src/plugins/configuration.md

@@ -0,0 +1,6 @@
+# Adding configuration to a plugin
+
+## The trade-off between re-usability and usability
+
+The more general the interface, the greater the re-usability, but it is then more complex and hence less usable.
+