Service broker manager has been started.

I inherited a SQL 2014 environment, and I see this in the log

“Service broker manager has been started.”.

I also see broker enabled on tempdb and msdb. For security reasons, I would like to disable on both of these system databases.

How can I verify if there is any communication happening on these 2 databases, are there any system tables to query or where it get logged?

AFAIK these 2 dbs have service broker enabled in SQL , do you have experience if any issue in disabling?

Thank you,