I find a way to show the Memory of the experience buffer.
You can open the file "ExperienceBuffer.m", which is in "...\Matlab\toolbox\rl\rl\+rl\+util".
In this file, you can the property value of the variable Memory. For example:
Then you set:
agentOpts.SaveExperienceBufferWithAgent = true;
agentOpts.ResetExperienceBufferBeforeTraining = false;
After your training, you can get the data in ''agent.ExperienceBuffer.Memory''
This also means that you can modify and use the training data.
I hope this method works for you : )