diff --git a/src/proc/control/argument-erasure.hpp b/src/proc/control/argument-erasure.hpp
index 69928a0dc..6345849d1 100644
--- a/src/proc/control/argument-erasure.hpp
+++ b/src/proc/control/argument-erasure.hpp
@@ -22,7 +22,8 @@
 
 
 /** @file argument-erasure.hpp
- ** TODO argument-erasure.hpp
+ ** Implementation helper to bind Proc-Layer commands with arbitrary argument tuples
+ ** @internal details of the [command handling framework](\ref command.hpp).
  */
 
 
diff --git a/src/proc/control/handling-pattern.cpp b/src/proc/control/handling-pattern.cpp
index 6d61c0cb0..da1188175 100644
--- a/src/proc/control/handling-pattern.cpp
+++ b/src/proc/control/handling-pattern.cpp
@@ -22,7 +22,8 @@
 
 
 /** @file handling-pattern.cpp
- ** TODO handling-pattern.cpp
+ ** Implementation of pre-defined command handling patterns
+ ** @internal detail of the Proc-Layer command handling framework.
  */
 
 
diff --git a/src/proc/control/mediaimpllib.hpp b/src/proc/control/mediaimpllib.hpp
index ed4fb7dc2..cf60e101d 100644
--- a/src/proc/control/mediaimpllib.hpp
+++ b/src/proc/control/mediaimpllib.hpp
@@ -22,7 +22,14 @@
 
 
 /** @file mediaimpllib.hpp
- ** TODO mediaimpllib.hpp
+ ** Abstraction to represent (metadata) of an external library to handle media data
+ ** Lumiera delegates most actual media data processing to well established external
+ ** libraries. While configuring the render process, a [stream type](streamtype.hpp)
+ ** framework is used to gain uniform access to heterogeneous media and processing
+ ** facilities. At some point, we need to integrate the individual capabilities of
+ ** the referenced libraries, though. This will be done with adapter implementations,
+ ** where the interface MediaImplLip defines those aspects actually used and required
+ ** by our internal processing.
  */
 
 
diff --git a/src/proc/control/pathmanager.cpp b/src/proc/control/pathmanager.cpp
index 5043a6428..46d97ff64 100644
--- a/src/proc/control/pathmanager.cpp
+++ b/src/proc/control/pathmanager.cpp
@@ -22,7 +22,9 @@
 
 
 /** @file pathmanager.cpp
- ** TODO pathmanager.cpp
+ ** Implementation functionality regarding decision about the proper
+ ** wiring and calculation strategy for rendering.
+ ** @todo placeholder as of 2014, development in this area is stalled
  */
 
 
diff --git a/src/proc/control/pathmanager.hpp b/src/proc/control/pathmanager.hpp
index b2a612dea..f925bc7e6 100644
--- a/src/proc/control/pathmanager.hpp
+++ b/src/proc/control/pathmanager.hpp
@@ -22,7 +22,11 @@
 
 
 /** @file pathmanager.hpp
- ** TODO pathmanager.hpp
+ ** Facility to decide upon the actual render strategy.
+ ** When wiring the various processing facilities to form a render nodes network,
+ ** at times there are multiple possibilities to reach a given goal. This opens
+ ** the opportunity for optimisation and to configure specific variants or flavours.
+ ** @todo this is a design draft and just defines a placeholder to indicate our plans.
  */
 
 
diff --git a/src/proc/control/proc-dispatcher.cpp b/src/proc/control/proc-dispatcher.cpp
index 9e7acd9a1..b0d8a62f2 100644
--- a/src/proc/control/proc-dispatcher.cpp
+++ b/src/proc/control/proc-dispatcher.cpp
@@ -22,7 +22,7 @@
 
 
 /** @file proc-dispatcher.cpp
- ** TODO proc-dispatcher.cpp
+ ** @todo merge from gui branch
  */
 
 
diff --git a/src/proc/control/stypemanager.cpp b/src/proc/control/stypemanager.cpp
index cfb5740bc..a0e6b9569 100644
--- a/src/proc/control/stypemanager.cpp
+++ b/src/proc/control/stypemanager.cpp
@@ -22,7 +22,7 @@
 
 
 /** @file stypemanager.cpp
- ** TODO stypemanager.cpp
+ ** Implementation functions of the stream type system
  */
 
 
diff --git a/src/proc/control/stypemanager.hpp b/src/proc/control/stypemanager.hpp
index 70261638f..f7fb27874 100644
--- a/src/proc/control/stypemanager.hpp
+++ b/src/proc/control/stypemanager.hpp
@@ -22,7 +22,9 @@
 
 
 /** @file stypemanager.hpp
- ** TODO stypemanager.hpp
+ ** Interface to the stream type system
+ ** @todo very crucial part of the design,
+ **       unfortunately development in this area is stalled since 2012
  */