Context Map (context_map) in syslog table is the place that provides insight or clues as to the problem script/piece of code causing the message in the system logs.
if you write the code and you know about the logging message if someone else does then it will be challenging for you trace with default view of system logs
So when you include the "Context Map" column in the list, which gives more information about piece of code caused the message. such as
ServiceNow node "_system_id" handled the script
User "_logger_in_user",
sys_id "record_sys_id" of the source script
Table name "table_name" and many more.
