Office365 Email Logger uses Microsoft Graph API processes email messages using the scheduler. Basic information about the message is saved into the repository database, msg files and attachments are saved on the disk
Microsoft Graph is the gateway to data and intelligence in Microsoft 365. It provides a unified programmability model that you can use to access the tremendous amount of data in Microsoft 365, Windows 10, and Enterprise Mobility + Security. Use the wealth of data in Microsoft Graph to build apps for organizations and consumers that interact with millions of users.
More information
https://docs.microsoft.com/en-us/graph/overview