rqt_bag has the same feature but the timestamps it shows are time when the message reached to rosbag record, not when the message was generated.
This tool shows message timestamp, with some auxiliary features such as topic ordering, coloring, and so on.
stamp_dump dumps all topics and message timestamps to a file named data.js. Note the stamps are message timestamp header.stamp, not rosbag view stamp, which is when the message was received by 'rosbag record').
main.html loads data.js and shows timelines, with some interacitve operations available.
cd tools
catkin_make
cd ..
./tools/devel/lib/stamp_dump/stamp_dump path-to-bag.bag