Where do I find the version of a Linux kernel source tree?

I have downloaded from a hardware vendor just a tarball of their Linux source tree (no Git repository metadata), is there a way to find out the version number of the kernel?

Is the version number usually stored in a file somewhere in the source tree?

I'd like to be able to do this without compiling and running the kernel.

You can find the version by running

make kernelversion

In the source tree

Check the top-level Makefile, an example of which is here. At the top of that, you should see something like:

VERSION = 3
PATCHLEVEL = 1
SUBLEVEL = 0
EXTRAVERSION = -pax
NAME = Custom Pax Version

The (admittedly minor) advantage of this method is that you only need the ability to view the files themselves rather than having to run a build process.