diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
 
-project(KWIN)
+project(KWin)
 set(PROJECT_VERSION "5.18.80")
 set(PROJECT_VERSION_MAJOR 5)
 
@@ -311,7 +311,6 @@
 set(KWIN_NAME "kwin")
 set(KWIN_INTERNAL_NAME_X11 "kwin_x11")
 set(KWIN_INTERNAL_NAME_WAYLAND "kwin_wayland")
-set(KWIN_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 
 # KWIN_HAVE_XRENDER_COMPOSITING - whether XRender-based compositing support is available: may be disabled
 if (KWIN_BUILD_XRENDER_COMPOSITING)
diff --git a/autotests/CMakeLists.txt b/autotests/CMakeLists.txt
--- a/autotests/CMakeLists.txt
+++ b/autotests/CMakeLists.txt
@@ -164,7 +164,7 @@
 ########################################################
 # Test ScriptedEffectLoader
 ########################################################
-include_directories(${KWIN_SOURCE_DIR})
+include_directories(${KWin_SOURCE_DIR})
 set(testScriptedEffectLoader_SRCS
     ../effectloader.cpp
     ../orientation_sensor.cpp
diff --git a/autotests/tabbox/CMakeLists.txt b/autotests/tabbox/CMakeLists.txt
--- a/autotests/tabbox/CMakeLists.txt
+++ b/autotests/tabbox/CMakeLists.txt
@@ -1,4 +1,4 @@
-include_directories(${KWIN_SOURCE_DIR})
+include_directories(${KWin_SOURCE_DIR})
 add_definitions(-DKWIN_UNIT_TEST)
 ########################################################
 # Test TabBox::ClientModel
diff --git a/effects/CMakeLists.txt b/effects/CMakeLists.txt
--- a/effects/CMakeLists.txt
+++ b/effects/CMakeLists.txt
@@ -1,7 +1,7 @@
 # KI18N Translation Domain for this library
 add_definitions(-DTRANSLATION_DOMAIN=\"kwin_effects\" -DEFFECT_BUILTINS)
 
-include_directories(${KWIN_SOURCE_DIR}) # for xcbutils.h
+include_directories(${KWin_SOURCE_DIR}) # for xcbutils.h
 
 set(kwin_effect_OWN_LIBS
     kwineffects
diff --git a/kcmkwin/common/CMakeLists.txt b/kcmkwin/common/CMakeLists.txt
--- a/kcmkwin/common/CMakeLists.txt
+++ b/kcmkwin/common/CMakeLists.txt
@@ -1,14 +1,14 @@
 # KI18N Translation Domain for this library
 add_definitions(-DTRANSLATION_DOMAIN=\"kcmkwincommon\")
 
-include_directories(${KWIN_SOURCE_DIR}/effects)
+include_directories(${KWin_SOURCE_DIR}/effects)
 
 set(kcmkwincommon_SRC
     effectsmodel.cpp
 )
 
 qt5_add_dbus_interface(kcmkwincommon_SRC
-    ${KWIN_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface
+    ${KWin_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface
 )
 
 add_library(kcmkwincommon SHARED ${kcmkwincommon_SRC})
diff --git a/kcmkwin/kwincompositing/CMakeLists.txt b/kcmkwin/kwincompositing/CMakeLists.txt
--- a/kcmkwin/kwincompositing/CMakeLists.txt
+++ b/kcmkwin/kwincompositing/CMakeLists.txt
@@ -14,7 +14,7 @@
 )
 
 qt5_add_dbus_interface(kwincomposing_SRC
-    ${KWIN_SOURCE_DIR}/org.kde.kwin.Compositing.xml kwin_compositing_interface
+    ${KWin_SOURCE_DIR}/org.kde.kwin.Compositing.xml kwin_compositing_interface
 )
 
 ki18n_wrap_ui(kwincomposing_SRC compositing.ui)
diff --git a/kcmkwin/kwinoptions/CMakeLists.txt b/kcmkwin/kwinoptions/CMakeLists.txt
--- a/kcmkwin/kwinoptions/CMakeLists.txt
+++ b/kcmkwin/kwinoptions/CMakeLists.txt
@@ -3,7 +3,7 @@
 add_definitions(-DTRANSLATION_DOMAIN=\"kcmkwm\")
 
 set(kcm_kwinoptions_PART_SRCS
-    ${KWIN_SOURCE_DIR}/effects/effect_builtins.cpp
+    ${KWin_SOURCE_DIR}/effects/effect_builtins.cpp
     main.cpp
     mouse.cpp
     windows.cpp
@@ -17,7 +17,7 @@
     moving.ui
 )
 
-qt5_add_dbus_interface(kcm_kwinoptions_PART_SRCS ${KWIN_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface)
+qt5_add_dbus_interface(kcm_kwinoptions_PART_SRCS ${KWin_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface)
 add_library(kcm_kwinoptions MODULE ${kcm_kwinoptions_PART_SRCS})
 target_link_libraries(kcm_kwinoptions Qt5::DBus KF5::Completion KF5::I18n KF5::ConfigWidgets KF5::Service KF5::WindowSystem)
 install(TARGETS kcm_kwinoptions DESTINATION ${PLUGIN_INSTALL_DIR})
diff --git a/kcmkwin/kwinscreenedges/CMakeLists.txt b/kcmkwin/kwinscreenedges/CMakeLists.txt
--- a/kcmkwin/kwinscreenedges/CMakeLists.txt
+++ b/kcmkwin/kwinscreenedges/CMakeLists.txt
@@ -1,12 +1,12 @@
 # KI18N Translation Domain for this library
 add_definitions(-DTRANSLATION_DOMAIN=\"kcmkwinscreenedges\")
 
-include_directories(${KWIN_SOURCE_DIR}/effects)
+include_directories(${KWin_SOURCE_DIR}/effects)
 set(kcm_screenedges_SRCS
     monitor.cpp
     screenpreviewwidget.cpp
 )
-qt5_add_dbus_interface(kcm_screenedges_SRCS ${KWIN_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface)
+qt5_add_dbus_interface(kcm_screenedges_SRCS ${KWin_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface)
 
 set(kcm_kwinscreenedges_PART_SRCS main.cpp ${kcm_screenedges_SRCS})
 ki18n_wrap_ui(kcm_kwinscreenedges_PART_SRCS main.ui)
diff --git a/kcmkwin/kwintabbox/CMakeLists.txt b/kcmkwin/kwintabbox/CMakeLists.txt
--- a/kcmkwin/kwintabbox/CMakeLists.txt
+++ b/kcmkwin/kwintabbox/CMakeLists.txt
@@ -1,19 +1,19 @@
 # KI18N Translation Domain for this library
 add_definitions(-DTRANSLATION_DOMAIN=\"kcm_kwintabbox\")
 
-include_directories(${KWIN_SOURCE_DIR}/effects ${KWIN_SOURCE_DIR}/tabbox ${KWIN_SOURCE_DIR})
+include_directories(${KWin_SOURCE_DIR}/effects ${KWin_SOURCE_DIR}/tabbox ${KWin_SOURCE_DIR})
 
 ########### next target ###############
 
 set(kcm_kwintabbox_PART_SRCS
-    ${KWIN_SOURCE_DIR}/tabbox/tabboxconfig.cpp
+    ${KWin_SOURCE_DIR}/tabbox/tabboxconfig.cpp
     layoutpreview.cpp
     main.cpp
     thumbnailitem.cpp
 )
 
 ki18n_wrap_ui(kcm_kwintabbox_PART_SRCS main.ui)
-qt5_add_dbus_interface(kcm_kwintabbox_PART_SRCS ${KWIN_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface)
+qt5_add_dbus_interface(kcm_kwintabbox_PART_SRCS ${KWin_SOURCE_DIR}/org.kde.kwin.Effects.xml kwin_effects_interface)
 
 add_library(kcm_kwintabbox MODULE ${kcm_kwintabbox_PART_SRCS})
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -10,13 +10,13 @@
 target_link_libraries(screenedgeshowtest Qt5::Widgets Qt5::X11Extras KF5::ConfigCore KF5::WindowSystem KF5::WaylandClient ${XCB_XCB_LIBRARY})
 
 set(libinputtest_SRCS
-    ${KWIN_SOURCE_DIR}/libinput/connection.cpp
-    ${KWIN_SOURCE_DIR}/libinput/context.cpp
-    ${KWIN_SOURCE_DIR}/libinput/device.cpp
-    ${KWIN_SOURCE_DIR}/libinput/events.cpp
-    ${KWIN_SOURCE_DIR}/libinput/libinput_logging.cpp
-    ${KWIN_SOURCE_DIR}/logind.cpp
-    ${KWIN_SOURCE_DIR}/udev.cpp
+    ${KWin_SOURCE_DIR}/libinput/connection.cpp
+    ${KWin_SOURCE_DIR}/libinput/context.cpp
+    ${KWin_SOURCE_DIR}/libinput/device.cpp
+    ${KWin_SOURCE_DIR}/libinput/events.cpp
+    ${KWin_SOURCE_DIR}/libinput/libinput_logging.cpp
+    ${KWin_SOURCE_DIR}/logind.cpp
+    ${KWin_SOURCE_DIR}/udev.cpp
     libinputtest.cpp
 )
 add_executable(libinputtest ${libinputtest_SRCS})