diff --git a/src/Drawer2D.c b/src/Drawer2D.c
index 206449ec5..3876983ed 100644
--- a/src/Drawer2D.c
+++ b/src/Drawer2D.c
@@ -415,7 +415,8 @@ void Drawer2D_ReducePadding_Height(int* height, int point, int scale) {
 	*height -= padding * 2;
 }
 
-void Drawer2D_Underline(Bitmap* bmp, int x, int y, int width, int height, BitmapCol col) {
+/* Quickly fills the given box region */
+static void Drawer2D_Underline(Bitmap* bmp, int x, int y, int width, int height, BitmapCol col) {
 	BitmapCol* row;
 	int xx, yy;
 
diff --git a/src/Drawer2D.h b/src/Drawer2D.h
index 20bda33fb..f768d68b4 100644
--- a/src/Drawer2D.h
+++ b/src/Drawer2D.h
@@ -55,7 +55,6 @@ CC_API void Drawer2D_BmpCopy(Bitmap* dst, int x, int y, Bitmap* src);
 /* Fills the area with the given colour. */
 CC_API void Drawer2D_Clear(Bitmap* bmp, BitmapCol col, int x, int y, int width, int height);
 
-void Drawer2D_Underline(Bitmap* bmp, int x, int y, int width, int height, BitmapCol col);
 /* Draws text using the given font at the given coordinates. */
 CC_API void Drawer2D_DrawText(Bitmap* bmp, struct DrawTextArgs* args, int x, int y);
 /* Returns how wide the given text would be when drawn. */
diff --git a/src/Logger.h b/src/Logger.h
index d6b00f28d..2583377c4 100644
--- a/src/Logger.h
+++ b/src/Logger.h
@@ -1,5 +1,5 @@
-#ifndef CC_ERRORHANDLER_H
-#define CC_ERRORHANDLER_H
+#ifndef CC_LOGGER_H
+#define CC_LOGGER_H
 #include "String.h"
 /* Support methods for logging errors.
    Copyright 2014-2019 ClassiCube | Licensed under BSD-3
@@ -12,20 +12,24 @@ typedef void (*Logger_DoWarn)(const String* msg);
 extern Logger_DoWarn Logger_WarnFunc;
 /* The title shown for warning dialogs. */
 extern const char* Logger_DialogTitle;
+/* Shows a warning message box with the given message. */
 void Logger_DialogWarn(const String* msg);
 
-/* Informs the user about a non-fatal error, with a message of form: "Error [result] when [place] */
+/* Informs the user about a non-fatal error. */
+/* Format: "Error [result] when [place]" */
 void Logger_SimpleWarn(cc_result res, const char* place);
-/* Informs the user about a non-fatal error, with a message of form: "Error [result] when [place] '[path]' */
+/* Informs the user about a non-fatal error. */
+/* Format: "Error [result] when [place] '[path]'" */
 void Logger_SimpleWarn2(cc_result res, const char* place, const String* path);
-/* Informs the user about a non-fatal error, with a message of either: 
-"Error [error desc] ([result]) when [place] or "Error [result] when [place] */
+/* Informs the user about a non-fatal error, with an optional meaning message. */
+/* Format: "Error [result] when [place]  \n  Error meaning: [desc]" */
 void Logger_SysWarn(cc_result res, const char* place, Logger_DescribeError describeErr);
-/* Informs the user about a non-fatal error, with a message of either:
-"Error [error desc] ([result]) when [place] 'path' or "Error [result] when [place] 'path' */
+/* Informs the user about a non-fatal error, with an optional meaning message. */
+/* Format: "Error [result] when [place] '[path]'  \n  Error meaning: [desc]" */
 void Logger_SysWarn2(cc_result res, const char* place, const String* path, Logger_DescribeError describeErr);
 
 /* Shows a warning for a failed DynamicLib_Load2/Get2 call. */
+/* Format: "Error [place] '[path]'  \n  Error meaning: [desc]" */
 void Logger_DynamicLibWarn(const char* place, const String* path);
 /* Shortcut for Logger_SysWarn with Platform_DescribeError */
 void Logger_Warn(cc_result res, const char* place);
diff --git a/src/Picking.h b/src/Picking.h
index 83ac35eb3..9eb4b7f5f 100644
--- a/src/Picking.h
+++ b/src/Picking.h
@@ -29,8 +29,11 @@ struct RayTracer {
 	Face Closest;        /* Face of the intersected block that is closet to the player */
 };
 
+/* Marks the given ray tracer as having no result. */
 void RayTracer_SetInvalid(struct RayTracer* t);
+/* Initialises the given ray tracer with the given origin and direction. */
 void RayTracer_Init(struct RayTracer* t, const Vec3* origin, const Vec3* dir);
+/* Moves to next grid cell position on the ray. */
 void RayTracer_Step(struct RayTracer* t);
 
 /* Determines the picked block based on the given origin and direction vector.