diff --git a/_setup_env.sh b/_setup_env.sh
new file mode 100644
index 0000000..379853f
--- /dev/null
+++ b/_setup_env.sh
@@ -0,0 +1,78 @@
+# Copyright (C) 2019 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This is an implementation detail of build.sh and friends. Do not source
+# directly as it will spoil your shell and make build.sh unusable. You have
+# been warned! If you have a good reason to source the result of this file into
+# a shell, please let kernel-team@android.com know and we are happy to help
+# with your use case.
+
+[ -n "$_SETUP_ENV_SH_INCLUDED" ] && return || _SETUP_ENV_SH_INCLUDED=1
+
+# TODO: Use a $(gettop) style method.
+export ROOT_DIR=$PWD
+
+export BUILD_CONFIG=${BUILD_CONFIG:-build.config}
+set -a
+. ${ROOT_DIR}/${BUILD_CONFIG}
+set +a
+
+export COMMON_OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
+export OUT_DIR=$(readlink -m ${COMMON_OUT_DIR}/${KERNEL_DIR})
+export DIST_DIR=$(readlink -m ${DIST_DIR:-${COMMON_OUT_DIR}/dist})
+
+echo "========================================================"
+echo "= build config: ${ROOT_DIR}/${BUILD_CONFIG}"
+cat ${ROOT_DIR}/${BUILD_CONFIG}
+
+# List of prebuilt directories shell variables to incorporate into PATH
+PREBUILTS_PATHS=(
+LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN
+LINUX_GCC_CROSS_COMPILE_ARM32_PREBUILTS_BIN
+CLANG_PREBUILT_BIN
+LZ4_PREBUILTS_BIN
+DTC_PREBUILTS_BIN
+LIBUFDT_PREBUILTS_BIN
+BUILDTOOLS_PREBUILT_BIN
+)
+
+for PREBUILT_BIN in "${PREBUILTS_PATHS[@]}"; do
+    PREBUILT_BIN=\${${PREBUILT_BIN}}
+    eval PREBUILT_BIN="${PREBUILT_BIN}"
+    if [ -n "${PREBUILT_BIN}" ]; then
+        # Mitigate dup paths
+        PATH=${PATH//"${ROOT_DIR}\/${PREBUILT_BIN}:"}
+        PATH=${ROOT_DIR}/${PREBUILT_BIN}:${PATH}
+    fi
+done
+export PATH
+
+echo
+echo "PATH=${PATH}"
+echo
+
+# verifies that defconfig matches the DEFCONFIG
+function check_defconfig() {
+    (cd ${OUT_DIR} && \
+     make ${CC_LD_ARG} O=${OUT_DIR} savedefconfig)
+    [ "$ARCH" = "x86_64" -o "$ARCH" = "i386" ] && local ARCH=x86
+    echo Verifying that savedefconfig matches ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG}
+    RES=0
+    diff ${OUT_DIR}/defconfig ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG} ||
+      RES=$?
+    if [ ${RES} -ne 0 ]; then
+        echo ERROR: savedefconfig does not match ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG}
+    fi
+    return ${RES}
+}
diff --git a/build.sh b/build.sh
index 8eb6b80..2edced3 100755
--- a/build.sh
+++ b/build.sh
@@ -159,7 +159,7 @@ SIGN_ALGO=sha512
 # BUILD_CONFIG.
 CC_ARG=${CC}
 
-source "${ROOT_DIR}/build/envsetup.sh"
+source "${ROOT_DIR}/build/_setup_env.sh"
 
 export MAKE_ARGS=$@
 export MODULES_STAGING_DIR=$(readlink -m ${COMMON_OUT_DIR}/staging)
diff --git a/build_abi.sh b/build_abi.sh
index b2f9170..b5c7566 100755
--- a/build_abi.sh
+++ b/build_abi.sh
@@ -28,8 +28,7 @@ export ROOT_DIR=$(readlink -f $(dirname $0)/..)
 set -e
 set -a
 
-source "${ROOT_DIR}/build/envsetup.sh"
-export ENVSETUP_SH_INCLUDED=1
+source "${ROOT_DIR}/build/_setup_env.sh"
 
 # inject CONFIG_DEBUG_INFO=y
 export POST_DEFCONFIG_CMDS="${POST_DEFCONFIG_CMDS} : && update_config_for_abi_dump"
diff --git a/build_test.sh b/build_test.sh
index 268af0b..17adaf5 100755
--- a/build_test.sh
+++ b/build_test.sh
@@ -36,7 +36,7 @@ export BUILD_CONFIG
 
 test=all_tests.sh
 set -e
-source ${ROOT_DIR}/envsetup.sh
+source ${ROOT_DIR}/_setup_env.sh
 export OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
 mkdir -p ${OUT_DIR}
 
diff --git a/envsetup.sh b/envsetup.sh
index 4ba9d17..09ab724 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -1,5 +1,3 @@
-# source this file. Don't run it.
-
 # Copyright (C) 2019 The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -14,70 +12,32 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# This is an implementation detail of build.sh and friends. Do not source
+# directly as it will spoil your shell and make build.sh unusable. You have
+# been warned! If you have a good reason to source the result of this file into
+# a shell, please let kernel-team@android.com know and we are happy to help
+# with your use case.
 
-# Usage:
-# $ build/build.sh
-#
-# Usage (deprecated):
-# $ source build/envsetup.sh  # to setup your path and cross compiler
-#                             # so that a kernel build command is just:
-# $ make -j24
-
-[ -n "$ENVSETUP_SH_INCLUDED" ] && return
-
-# TODO: Use a $(gettop) style method.
-export ROOT_DIR=$PWD
-
-export BUILD_CONFIG=${BUILD_CONFIG:-build.config}
-set -a
-. ${ROOT_DIR}/${BUILD_CONFIG}
-set +a
-
-export COMMON_OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
-export OUT_DIR=$(readlink -m ${COMMON_OUT_DIR}/${KERNEL_DIR})
-export DIST_DIR=$(readlink -m ${DIST_DIR:-${COMMON_OUT_DIR}/dist})
 
-echo "========================================================"
-echo "= build config: ${ROOT_DIR}/${BUILD_CONFIG}"
-cat ${ROOT_DIR}/${BUILD_CONFIG}
-
-# List of prebuilt directories shell variables to incorporate into PATH
-PREBUILTS_PATHS=(
-LINUX_GCC_CROSS_COMPILE_PREBUILTS_BIN
-LINUX_GCC_CROSS_COMPILE_ARM32_PREBUILTS_BIN
-CLANG_PREBUILT_BIN
-LZ4_PREBUILTS_BIN
-DTC_PREBUILTS_BIN
-LIBUFDT_PREBUILTS_BIN
-BUILDTOOLS_PREBUILT_BIN
-)
-
-for PREBUILT_BIN in "${PREBUILTS_PATHS[@]}"; do
-    PREBUILT_BIN=\${${PREBUILT_BIN}}
-    eval PREBUILT_BIN="${PREBUILT_BIN}"
-    if [ -n "${PREBUILT_BIN}" ]; then
-        # Mitigate dup paths
-        PATH=${PATH//"${ROOT_DIR}\/${PREBUILT_BIN}:"}
-        PATH=${ROOT_DIR}/${PREBUILT_BIN}:${PATH}
-    fi
-done
-export PATH
-
-echo
-echo "PATH=${PATH}"
-echo
+# This is a dummy to not break people that have a workflow that includes
+# sourcing build/envsetup.sh into a shell when working with Android repo.
+# The actual functionality of this script has been moved to _setup_env.sh.
+#
+# It turns out that build/envsetup.sh was sourced into the shell by a lot of
+# people. Mostly due to the fact that old documentation asked people to do so
+# (including this script itself). Unfortunately, this causes more harm than it
+# does any good. Mostly it spoils the shell with environment variables that are
+# only valid in the context of a very specific build configuration. To overcome
+# this, the content of this file has been moved to _setup_env.sh and callers
+# within this project have been adjusted. This script serves as a dummy to not
+# break people sourcing it, but it will from now on emit a deprecation warning.
+# That script might be removed at a later time.
+#
+# For further information on the Android Kernel build process with the tooling
+# of this project, please refer to
+# https://source.android.com/setup/build/building-kernels.
+#
+# For any questions or concerns, please contact kernel-team@android.com.
 
-# verifies that defconfig matches the DEFCONFIG
-function check_defconfig() {
-    (cd ${OUT_DIR} && \
-     make ${CC_LD_ARG} O=${OUT_DIR} savedefconfig)
-    [ "$ARCH" = "x86_64" -o "$ARCH" = "i386" ] && local ARCH=x86
-    echo Verifying that savedefconfig matches ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG}
-    RES=0
-    diff ${OUT_DIR}/defconfig ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG} ||
-      RES=$?
-    if [ ${RES} -ne 0 ]; then
-        echo ERROR: savedefconfig does not match ${KERNEL_DIR}/arch/${ARCH}/configs/${DEFCONFIG}
-    fi
-    return ${RES}
-}
+echo "Sourcing 'build/envsetup.sh' for Android Kernels is deprecated and no longer valid!"
+echo "Please refer to the documentation in said script for details."
diff --git a/static_analysis/checkpatch.sh b/static_analysis/checkpatch.sh
index 4857d26..8545c8f 100755
--- a/static_analysis/checkpatch.sh
+++ b/static_analysis/checkpatch.sh
@@ -22,7 +22,7 @@ export STATIC_ANALYSIS_SRC_DIR=$(dirname $(readlink -f $0))
 
 ROOT_DIR="${STATIC_ANALYSIS_SRC_DIR}/../../"
 pushd ${ROOT_DIR}
-source ${STATIC_ANALYSIS_SRC_DIR}/../envsetup.sh
+source ${STATIC_ANALYSIS_SRC_DIR}/../_setup_env.sh
 export OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
 export DIST_DIR=$(readlink -m ${DIST_DIR:-${OUT_DIR}/dist})
 mkdir -p ${DIST_DIR}
diff --git a/static_analysis/checkpatch_presubmit.sh b/static_analysis/checkpatch_presubmit.sh
index d057601..fc4f550 100755
--- a/static_analysis/checkpatch_presubmit.sh
+++ b/static_analysis/checkpatch_presubmit.sh
@@ -22,7 +22,7 @@ set -e
 
 export STATIC_ANALYSIS_SRC_DIR=$(dirname $(readlink -f $0))
 
-source ${STATIC_ANALYSIS_SRC_DIR}/../envsetup.sh
+source ${STATIC_ANALYSIS_SRC_DIR}/../_setup_env.sh
 export OUT_DIR=$(readlink -m ${OUT_DIR:-${ROOT_DIR}/out/${BRANCH}})
 export DIST_DIR=$(readlink -m ${DIST_DIR:-${OUT_DIR}/dist})