diff --git a/y2019/control_loops/drivetrain/BUILD b/y2019/control_loops/drivetrain/BUILD
index 677726e..de52215 100644
--- a/y2019/control_loops/drivetrain/BUILD
+++ b/y2019/control_loops/drivetrain/BUILD
@@ -88,6 +88,7 @@
     srcs = [
         "camera.q",
     ],
+    visibility = ["//visibility:public"],
 )
 
 cc_library(
diff --git a/y2019/control_loops/drivetrain/camera.q b/y2019/control_loops/drivetrain/camera.q
index 5add759..6ef6f49 100644
--- a/y2019/control_loops/drivetrain/camera.q
+++ b/y2019/control_loops/drivetrain/camera.q
@@ -1,7 +1,6 @@
 package y2019.control_loops.drivetrain;
 
-// These structures have a nearly one-to-one correspondence to those in
-// //y2019/jevois:structures.h. Please refer to that file for details.
+// See the Target structure in //y2019/jevois:structures.h for documentation.
 struct CameraTarget {
   float distance;
   float height;
@@ -10,17 +9,17 @@
 };
 
 message CameraFrame {
-  // monotonic time in nanoseconds at which frame was taken (note structure.h
-  // uses age).
+  // Number of nanoseconds since the aos::monotonic_clock epoch at which this
+  // frame was captured.
   int64_t timestamp;
 
   // Number of targets actually in this frame.
   uint8_t num_targets;
 
-  // Buffer for the targets
+  // Buffer for the targets.
   CameraTarget[3] targets;
 
-  // Index of the camera with which this frame was taken:
+  // Index of the camera position (not serial number) which this frame is from.
   uint8_t camera;
 };