diff --git a/src/newgrf_spritegroup.h b/src/newgrf_spritegroup.h
--- a/src/newgrf_spritegroup.h
+++ b/src/newgrf_spritegroup.h
@@ -56,13 +56,14 @@ extern SpriteGroupPool _spritegroup_pool
 /* Common wrapper for all the different sprite group types */
 struct SpriteGroup : SpriteGroupPool::PoolItem<&_spritegroup_pool> {
 protected:
-	SpriteGroup(SpriteGroupType type) : type(type) {}
+	SpriteGroup(SpriteGroupType type) : nfo_line(0), type(type) {}
 	/** Base sprite group resolver */
 	virtual const SpriteGroup *Resolve(ResolverObject &object) const { return this; };
 
 public:
 	virtual ~SpriteGroup() {}
 
+	uint32 nfo_line;
 	SpriteGroupType type;
 
 	virtual SpriteID GetResult() const { return 0; }
@@ -398,6 +399,18 @@ struct ResolverObject {
 		this->used_triggers = 0;
 		memset(this->reseed, 0, sizeof(this->reseed));
 	}
+
+	/**
+	 * Get the feature number being resolved for.
+	 * This function is mainly intended for the callback profiling feature.
+	 */
+	virtual GrfSpecFeature GetFeature() const { return GSF_INVALID; }
+	/**
+	 * Get an identifier for the item being resolved.
+	 * This function is mainly intended for the callback profiling feature,
+	 * and should return an identifier recognisable by the NewGRF developer.
+	 */
+	virtual uint32 GetDebugID() const { return 0; }
 };
 
 #endif /* NEWGRF_SPRITEGROUP_H */