In Login History, view logins into connected apps that use user-agent or username-password login flows. With new OAuth Flow Enhancements, you can monitor use of these insecure flows to determine the impact of blocking them.
Where: This change applies to Lightning Experience and Salesforce Classic in all editions.
Why: You can block user-agent and username-password login flows so that developers can’t use them to build new integrations. Blocking these flows is likely to break mobile applications, including those developed by Salesforce such as the Salesforce mobile app and the Field Service mobile app. Blocking is also likely to break managed packages. To avoid disruptions, monitor logins to see which apps use these flows.
How: From Setup, in the Quick Find box, enter Login History, and then click Login History. Click Create New View.
To restrict the new view to show only login subtype data, under Step 2: Specify Filter Criteria, select Login Subtype and equals, then click 
and select the login subtype values to include.
To display the Login Subtype column in the new view, under Step 3: Select Fields to Display, add the Login Subtype field. Finish creating the Login History view, and then save.
Monitor Connected App Logins That Use Insecure Flows (salesforce.com)