Thank you for your question.
*.connlog files contain log info for a session about the connection attemps and communilation details. It is a bit more detailed than the system logs in the normal session window, and also more technical. They are needed only for solving support issues.
*.plog file contains chat log data during the session, until the log is not saved to the Web site. It garanties the logs can be retrived even when the Technician Console crashes, before saving the logs to the Data Base.