Debug log of Connection user in salesforce to salesforce Integration

When configuring Debug Logs, you cannot choose a Salesforce to Salesforce Connection User from the User Lookup, but there is a workaround to achieve this.

To Capture Debug Logs for a Connection User open the following URL in your browser:

https://[salesforceInstance].salesforce.com/p/setup/layout/AddApexDebugLogUser?retURL=%2Fsetup%2Fui%2FlistApexTraces.apexp&UserLookupInput_lkid=[connectingUserId]&UserLookupInput=[ConnectingUser Name]

Replace [salesforceInstance] with your salesforce instance, 

UserLookupInput_lkid is the ID of the Connection User and UserLookupInput is the User name. 

You can find the user ID of the connection user, by inspecting the CreatedById for a record created by this user.