Why is EmailHeaders analyzer showing blank "from" information while there is one in the X-Received of email header

I am trying to understand the email header and I found out using email header checker (i.g. mxtoolbox) can easily get the information. But I wonder how does this work?

For example, I have a email header showing like this:

Received: from DM5PR04MB0251.namprd04.prod.outlook.com (::1) by
 DM6PR04MB6592.namprd04.prod.outlook.com with HTTPS; Tue, 13 Sep 2022 00:17:52
 +0000
Received: from DB6PR1001CA0016.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:4:b7::26)
 by DM5PR04MB0251.namprd04.prod.outlook.com (2603:10b6:3:74::12) with
 Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5612.22; Tue, 13 Sep
 2022 00:17:51 +0000
Received: from DB8EUR06FT019.eop-eur06.prod.protection.outlook.com
 (2603:10a6:4:b7:cafe::4b) by DB6PR1001CA0016.outlook.office365.com
 (2603:10a6:4:b7::26) with Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5612.14 via Frontend
 Transport; Tue, 13 Sep 2022 00:17:51 +0000

...
...

And it shows blank in the from information.

Do you know why is this?