what is the purpose of "LOCALVERSION" variable in scripts/setlocalversion?

[Chinmay V S]

> i was unaware of the apparently independent variable "LOCALVERSION"
> which is used in that assignment.
>
>   there's precious little mention of that variable ... under what
> circumstances does one set it?

I have sometimes seen a "+" or a short-commit-sha appended when
building kernel in a local git repository with uncommitted/committed
changes.

Also i suppose one could run make LOCALVERSION=<unique-string-here> to
help identify a kernel image by the embedded <unique-string> if
required at a later time.

As the image name is one of the first things to be printed in the
kernel/dmesg logs, it helps map error logs to their respective builds.