Vbmeta - why is it part of the Magisk install howto?

[Smojo]

While I was about to root a FP3 I was reading the Magisk install guide again and I was wondering why vbmeta is part of the Magisk guide at all - even clearly stated as optional.

(Optional) If your device has a separate vbmeta partition, you can patch the vbmeta partition with command:
fastboot flash vbmeta --disable-verity --disable-verification vbmeta.img (note that it may wipe your data)

First I tried to understand what vbmeta actually is - found this nice page:
https://android.googlesource.com/platform/external/avb/+/master/README.md#The-VBMeta-struct

So high level explained vbmeta is a partition, which consists a lot of Meta-Data (hashes, hash trees, signing keys, etc.). It is part of / needed for AVB (Android Verified Boot).

I will probably never be an expert of this, but I was ok with the stuff I understood and wanted now to understand the role in the root process. But I could not really wrap my head around it.

Rooting will make certain things (relock bootloader, verified boot, OTA Updates [at least not without following workarounds]) impossible anyway.

So can one explain why it is actually in there? In which situations would it make sense to flash it?

[llluuuzzziii]

@Smojo

So can one explain why it is actually in there? In which situations would it make sense to flash it?

If the builder of the operating system has protected the contents of the /userdata partition (dm-verity). When the command was given and the bootloader did a factory reset, the partition was protected.