diff --git a/cmake/modules/copy_python_files_in_subdir.cmake b/cmake/modules/copy_python_files_in_subdir.cmake
index be477f6066c..0cd33a7e655 100644
--- a/cmake/modules/copy_python_files_in_subdir.cmake
+++ b/cmake/modules/copy_python_files_in_subdir.cmake
@@ -9,9 +9,12 @@ SPDX-License-Identifier: GPL-2.0-or-later
 #]]
 
 function(copy_python_files_in_subdir dir_name dst_prefix)
-  cmake_parse_arguments(G "PRE_BUILD;PRE_LINK;POST_BUILD" "TARGET" "" ${ARGN})
+  cmake_parse_arguments(G "PRE_BUILD;PRE_LINK;POST_BUILD" "TARGET" "EXCLUDE" ${ARGN})
 
   file(GLOB PY_FILES "${CMAKE_CURRENT_SOURCE_DIR}/${dir_name}/*.py")
+  foreach(exclude_file ${G_EXCLUDE})
+    list(FILTER PY_FILES EXCLUDE REGEX ".*/${exclude_file}")
+  endforeach()
 
   if(DEFINED G_TARGET)
     if(${G_PRE_BUILD})
diff --git a/include/Make/Install.make b/include/Make/Install.make
index 799a695e80d..44fcd0dcf34 100644
--- a/include/Make/Install.make
+++ b/include/Make/Install.make
@@ -95,11 +95,14 @@ FONTCAP = etc/fontcap
 TMPGISRC = demolocation/.grassrc$(GRASS_VERSION_MAJOR)$(GRASS_VERSION_MINOR)
 PLATMAKE = include/Make/Platform.make
 GRASSMAKE = include/Make/Grass.make
+RESOURCE_PATHS = etc/python/grass/app/resource_paths.py
 
 real-install: | $(DESTDIR) $(DESTDIR)$(INST_DIR) $(DESTDIR)$(UNIX_BIN)
 	-tar cBCf $(GISBASE) - . | tar xBCf $(DESTDIR)$(INST_DIR) - 2>/dev/null
 	-rm $(DESTDIR)$(INST_DIR)/$(GRASS_NAME).tmp
+	-rm $(DESTDIR)$(INST_DIR)/$(RESOURCE_PATHS)
 	$(MAKE) $(STARTUP)
+	$(MAKE) $(DESTDIR)$(INST_DIR)/$(RESOURCE_PATHS)
 
 	-rm $(DESTDIR)$(INST_DIR)/$(FONTCAP)
 	$(MAKE) $(DESTDIR)$(INST_DIR)/$(FONTCAP)
@@ -122,12 +125,17 @@ $(DESTDIR)$(INST_DIR) $(DESTDIR)$(UNIX_BIN):
 	$(MAKE_DIR_CMD) $@
 
 $(STARTUP): $(ARCH_DISTDIR)/$(GRASS_NAME).tmp
-	sed -e 's#'@GISBASE_INSTALL_PATH@'#'$(INST_DIR)'#g' \
+	sed -e 's#'@GRASS_PREFIX@'#'$(INST_DIR)'#g' \
 	    -e 's#'@LD_LIBRARY_PATH_VAR@'#'$(LD_LIBRARY_PATH_VAR)'#g' \
 	    -e 's#'@CONFIG_PROJSHARE@'#'$(PROJSHARE)'#g' \
 	    $< > $@
 	-$(CHMOD) a+x $@
 
+$(DESTDIR)$(INST_DIR)/$(RESOURCE_PATHS): $(ARCH_DISTDIR)/resource_paths.py
+	sed -e 's#'@GRASS_PREFIX@'#'$(INST_DIR)'#g' \
+	    -e 's#'@GISBASE_INSTALL_PATH@'##g' \
+	    $< > $@
+
 define fix_gisbase
 sed -e 's#$(GISBASE)#$(INST_DIR)#g' $< > $@
 endef
diff --git a/lib/init/CMakeLists.txt b/lib/init/CMakeLists.txt
index 89509db5c69..9f52c2ecf47 100644
--- a/lib/init/CMakeLists.txt
+++ b/lib/init/CMakeLists.txt
@@ -59,12 +59,14 @@ elseif(WIN32)
 endif()
 
 # configure and install grass.py
-set(GISBASE_INSTALL_PATH ${RUNTIME_GISBASE})
+set(GRASS_PREFIX ${OUTDIR})
+set(GRASS_PYDIR ${GRASS_INSTALL_PYDIR})
 configure_file(grass.py ${OUTDIR}/${CMAKE_INSTALL_BINDIR}/${START_UP} @ONLY)
 
-set(GISBASE_INSTALL_PATH ${GISBASE})
+set(GRASS_PREFIX ${CMAKE_INSTALL_PREFIX})
 configure_file(grass.py ${CMAKE_CURRENT_BINARY_DIR}/${START_UP} @ONLY)
-unset(GISBASE_INSTALL_PATH)
+unset(GRASS_PYDIR)
+unset(GRASS_PREFIX)
 
 install(PROGRAMS ${CMAKE_CURRENT_BINARY_DIR}/${START_UP}
         DESTINATION ${CMAKE_INSTALL_BINDIR})
diff --git a/lib/init/Makefile b/lib/init/Makefile
index 99366b060a9..8a7127189d9 100644
--- a/lib/init/Makefile
+++ b/lib/init/Makefile
@@ -77,6 +77,8 @@ endif
 	-e 's#@LD_LIBRARY_PATH_VAR@#$(LD_LIBRARY_PATH_VAR)#' \
 	-e 's#@START_UP@#$(START_UP)#' \
 	-e 's#@CONFIG_PROJSHARE@#$(PROJSHARE)#' \
+	-e 's#@GRASS_PREFIX@#$(RUN_GISBASE)#' \
+	-e 's#@GRASS_PYDIR@#etc/python#' \
 	$< > $@
 	chmod +x $@
 
@@ -91,6 +93,7 @@ $(ARCH_DISTDIR)/$(START_UP).tmp: grass.py
 	-e 's#@GRASS_CONFIG_DIR@#$(GRASS_CONFIG_DIR)#' \
 	-e 's#@LD_LIBRARY_PATH_VAR@#$(LD_LIBRARY_PATH_VAR)#' \
 	-e 's#@CONFIG_PROJSHARE@#$(PROJSHARE)#' \
+	-e 's#@GRASS_PYDIR@#etc/python#' \
 	$< > $@
 
 $(ETC)/echo$(EXE) $(ETC)/run$(EXE): $(ETC)/%$(EXE): $(OBJDIR)/%.o
diff --git a/lib/init/grass.py b/lib/init/grass.py
index add393d29e1..11caba10c9d 100755
--- a/lib/init/grass.py
+++ b/lib/init/grass.py
@@ -71,6 +71,8 @@
 # for wxpath
 _WXPYTHON_BASE = None
 
+GISBASE = None
+
 try:
     # Python >= 3.11
     ENCODING = locale.getencoding()
@@ -81,25 +83,7 @@
     print("Default locale not found, using UTF-8")  # intentionally not translatable
 
 # The "@...@" variables are being substituted during build process
-#
-# TODO: should GISBASE be renamed to something like GRASS_PATH?
-# GISBASE marks complete runtime, so no need to get it here when
-# setting it up, possible scenario: existing runtime and starting
-# GRASS in that, we want to overwrite the settings, not to take it
-# possibly same for GRASS_PROJSHARE and others but maybe not
-#
-# We need to simultaneously make sure that:
-# - we get GISBASE from os.environ if it is defined (doesn't this mean that we are
-#   already inside a GRASS session? If we are, why do we need to run this script
-#   again???).
-# - GISBASE exists as an ENV variable
-#
-# pmav99: Ugly as hell, but that's what the code before the refactoring was doing.
-if "GISBASE" in os.environ and len(os.getenv("GISBASE")) > 0:
-    GISBASE = os.path.normpath(os.environ["GISBASE"])
-else:
-    GISBASE = os.path.normpath("@GISBASE_INSTALL_PATH@")
-    os.environ["GISBASE"] = GISBASE
+
 CMD_NAME = "@START_UP@"
 GRASS_VERSION = "@GRASS_VERSION_NUMBER@"
 GRASS_VERSION_MAJOR = "@GRASS_VERSION_MAJOR@"
@@ -2103,9 +2087,16 @@ def validate_cmdline(params: Parameters) -> None:
 
 def find_grass_python_package() -> None:
     """Find path to grass package and add it to path"""
-    if os.path.exists(gpath("etc", "python")):
-        path_to_package = gpath("etc", "python")
-        sys.path.append(path_to_package)
+    GRASS_PREFIX = "@GRASS_PREFIX@"
+
+    if "GRASS_PYDIR" in os.environ and len(os.getenv("GRASS_PYDIR")) > 0:
+        GRASS_PYDIR = os.path.normpath(os.environ["GRASS_PYDIR"])
+    else:
+        GRASS_PYDIR = os.path.normpath(os.path.join(GRASS_PREFIX, "@GRASS_PYDIR@"))
+        os.environ["GRASS_PYDIR"] = GRASS_PYDIR
+
+    if os.path.exists(GRASS_PYDIR):
+        sys.path.append(GRASS_PYDIR)
         # now we can import stuff from grass package
     else:
         # Not translatable because we don't have translations loaded.
@@ -2115,6 +2106,12 @@ def find_grass_python_package() -> None:
         )
         raise RuntimeError(msg)
 
+    from grass.app import resource_paths
+
+    resource_paths.set_resource_paths()
+    global GISBASE
+    GISBASE = resource_paths.GISBASE
+
 
 def main() -> None:
     """The main function which does the whole setup and run procedure
diff --git a/python/grass/CMakeLists.txt b/python/grass/CMakeLists.txt
index eeb0be1deb2..6ed3c8a21a8 100644
--- a/python/grass/CMakeLists.txt
+++ b/python/grass/CMakeLists.txt
@@ -1,5 +1,4 @@
 set(PYDIRS
-    app
     benchmark
     exceptions
     grassdb
@@ -28,12 +27,23 @@ set(PYDIR_GRASS ${GRASS_INSTALL_PYDIR}/grass)
 foreach(pydir ${PYDIRS})
   copy_python_files_in_subdir(${pydir} ${PYDIR_GRASS})
 endforeach()
+copy_python_files_in_subdir(app ${PYDIR_GRASS} EXCLUDE resource_paths.py)
 
 configure_file(__init__.py ${OUTDIR}/${PYDIR_GRASS}/ COPYONLY)
 configure_file(script/setup.py ${OUTDIR}/${PYDIR_GRASS}/script/setup.py
                COPYONLY)
 
-set(pydir_targets ${PYDIRS})
+# configure and install resource_paths.py
+set(GRASS_PREFIX ${OUTDIR})
+set(GISBASE_INSTALL_PATH ${GISBASE_DIR})
+configure_file(app/resource_paths.py ${OUTDIR}/${PYDIR_GRASS}/app/resource_paths.py @ONLY)
+
+set(GRASS_PREFIX ${CMAKE_INSTALL_PREFIX})
+configure_file(app/resource_paths.py ${CMAKE_CURRENT_BINARY_DIR}/resource_paths.py @ONLY)
+unset(GISBASE_INSTALL_PATH)
+unset(GRASS_PREFIX)
+
+set(pydir_targets ${PYDIRS} app)
 list(TRANSFORM pydir_targets REPLACE "/" "_")
 list(TRANSFORM pydir_targets PREPEND "python_")
 
@@ -44,4 +54,7 @@ add_custom_target(
 
 set_target_properties(LIB_PYTHON PROPERTIES FOLDER lib)
 
-install(DIRECTORY ${OUTDIR}/${PYDIR_GRASS} DESTINATION ${GRASS_INSTALL_PYDIR})
+install(DIRECTORY ${OUTDIR}/${PYDIR_GRASS} DESTINATION ${GRASS_INSTALL_PYDIR}
+        PATTERN "*/resource_paths.py" EXCLUDE)
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/resource_paths.py
+        DESTINATION ${GRASS_INSTALL_PYDIR}/grass/app)
diff --git a/python/grass/app/Makefile b/python/grass/app/Makefile
index eebbcef8f12..9fe5ba95259 100644
--- a/python/grass/app/Makefile
+++ b/python/grass/app/Makefile
@@ -14,7 +14,20 @@ MODULES = \
 PYFILES := $(patsubst %,$(DSTDIR)/%.py,$(MODULES) __init__)
 PYCFILES := $(patsubst %,$(DSTDIR)/%.pyc,$(MODULES) __init__)
 
-default: $(PYFILES) $(PYCFILES)
+PYFILES := $(filter-out resource_paths.py,$(PYFILES))
+PYCFILES := $(filter-out resource_paths.pyc,$(PYCFILES))
+
+default: $(PYFILES) $(PYCFILES) $(DSTDIR)/resource_paths.py $(ARCH_DISTDIR)/resource_paths.py
+
+$(DSTDIR)/resource_paths.py: resource_paths.py
+	rm -f $@
+	sed \
+	-e 's#@GRASS_PREFIX@#$(RUN_GISBASE)#' \
+	-e 's#@GISBASE_INSTALL_PATH@##' \
+	$< > $@
+
+$(ARCH_DISTDIR)/resource_paths.py:
+	cp resource_paths.py $@
 
 $(DSTDIR):
 	$(MKDIR) $@
diff --git a/python/grass/app/resource_paths.py b/python/grass/app/resource_paths.py
new file mode 100644
index 00000000000..18bc7754949
--- /dev/null
+++ b/python/grass/app/resource_paths.py
@@ -0,0 +1,31 @@
+"""
+
+(C) 2025 by Nicklas Larsson and the GRASS Development Team
+
+This program is free software under the GNU General Public
+License (>=v2). Read the file COPYING that comes with GRASS
+for details.
+
+
+This is not a stable part of the API. Use at your own risk.
+
+The "@...@" variables are being substituted during build process
+
+"""
+
+import os
+
+GRASS_PREFIX = None
+GISBASE = None
+
+
+def set_resource_paths():
+    global GRASS_PREFIX, GISBASE
+
+    GRASS_PREFIX = "@GRASS_PREFIX@"
+
+    if "GISBASE" in os.environ and len(os.getenv("GISBASE")) > 0:
+        GISBASE = os.path.normpath(os.environ["GISBASE"])
+    else:
+        GISBASE = os.path.normpath(os.path.join(GRASS_PREFIX, "@GISBASE_INSTALL_PATH@"))
+        os.environ["GISBASE"] = GISBASE