After the configuration of LMS365 and accepting the consent these three applications will be automatically added:
LMS365 is the LMS365 admin side web application. This application requests permissions to LMS365 API, Graph API, SharePoint, etc. You can see the full list of the permissions when accepting the consent.
LMS365 API is LMS365 API application the clients request permissions on.
LMS365 API Client is native client for the LMS365 API. This application is primarily used in LMS365 mobile application. It is also used for the Teams and Web endpoints.
NOTE: If you want to hide the application from the All Applications panel, follow the Microsoft instruction on how to hide enterprise application from end-users in Azure Active Directory.