README: Reduce the textdump; describe the project

Rework the README to make it a little easier for new users. This is the
first file many will see when persuing the FreeBSD source code so

- remove some of the text describes how to build. This is better covered
in the linked documentation.
- add a small blurb for what FreeBSD is. Some users might find this
document through features such as github search so they may not even
know what the project is

generally, gear this file for the new, accidental, or casual user rather
than towards someone seeking fuller documentation.

README

@@ -2,35 +2,25 @@ This is the top level of the FreeBSD source directory.  This file
 was last revised on:
 $FreeBSD$
 
+FreeBSD is an operating system used to power modern servers,
+desktops, and embedded platforms. A large community has
+continually developed it for more than thirty years. Its
+advanced networking, security, and storage features have
+made FreeBSD the platform of choice for many of the
+busiest web sites and most pervasive embedded networking
+and storage devices.
+
 For copyright information, please see the file COPYRIGHT in this
-directory (additional copyright information also exists for some
+directory. Additional copyright information also exists for some
 sources in this tree - please see the specific source directories for
-more information).
+more information.
 
 The Makefile in this directory supports a number of targets for
-building components (or all) of the FreeBSD source tree.  See build(7)
-and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html
+building components (or all) of the FreeBSD source tree.  See build(7), config(8),
+https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and
+https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
 for more information, including setting make(1) variables.
 
-The `buildkernel` and `installkernel` targets build and install
-the kernel and the modules (see below).  Please see the top of
-the Makefile in this directory for more information on the
-standard build targets and compile-time flags.
-
-Building a kernel is a somewhat more involved process.  See build(7), config(8),
-and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
-for more information.
-
-Note: If you want to build and install the kernel with the
-`buildkernel` and `installkernel` targets, you might need to build
-world before.  More information is available in the handbook.
-
-The kernel configuration files reside in the sys/<arch>/conf
-sub-directory.  GENERIC is the default configuration used in release builds.
-NOTES contains entries and documentation for all possible
-devices, not just those commonly used.
-
-
 Source Roadmap:
 ---------------
 
@@ -70,6 +60,8 @@ stand		Boot loader sources.
 
 sys		Kernel sources.
 
+sys/<arch>/conf Kernel configuration file
+
 tests		Regression tests which can be run by Kyua.  See tests/README
 		for additional information.
 

README.md

@@ -4,35 +4,25 @@ This is the top level of the FreeBSD source directory.  This file
 was last revised on:
 $FreeBSD$
 
+FreeBSD is an operating system used to power modern servers,
+desktops, and embedded platforms. A large community has
+continually developed it for more than thirty years. Its
+advanced networking, security, and storage features have
+made FreeBSD the platform of choice for many of the
+busiest web sites and most pervasive embedded networking
+and storage devices.
+
 For copyright information, please see the file COPYRIGHT in this
-directory (additional copyright information also exists for some
+directory. Additional copyright information also exists for some
 sources in this tree - please see the specific source directories for
-more information).
+more information.
 
 The Makefile in this directory supports a number of targets for
-building components (or all) of the FreeBSD source tree.  See build(7)
-and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html
+building components (or all) of the FreeBSD source tree.  See build(7), config(8),
+https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and
+https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
 for more information, including setting make(1) variables.
 
-The `buildkernel` and `installkernel` targets build and install
-the kernel and the modules (see below).  Please see the top of
-the Makefile in this directory for more information on the
-standard build targets and compile-time flags.
-
-Building a kernel is a somewhat more involved process.  See build(7), config(8),
-and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html
-for more information.
-
-Note: If you want to build and install the kernel with the
-`buildkernel` and `installkernel` targets, you might need to build
-world before.  More information is available in the handbook.
-
-The kernel configuration files reside in the `sys/<arch>/conf`
-sub-directory.  GENERIC is the default configuration used in release builds.
-NOTES contains entries and documentation for all possible
-devices, not just those commonly used.
-
-
 Source Roadmap:
 ---------------
 ```
@@ -72,6 +62,8 @@ stand		Boot loader sources.
 
 sys		Kernel sources.
 
+sys/<arch>/conf Kernel configuration file
+
 tests		Regression tests which can be run by Kyua.  See tests/README
 		for additional information.