Open File Manager And Complete Midiag.apk Installation. Then Try Again 99%

The error message "Open File Manager and complete midiag.apk installation. Then try again" a specific instruction common on Xiaomi (MIUI/HyperOS) devices when attempting to enable Diagnostic (Diag) Mode

Step 1: Enable Installation from Unknown Sources

Some versions of MIDIag require extra permissions. After installing: The error message "Open File Manager and complete midiag

Step 6: Open the installed app

What Is MIDIag.apk?