diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index c79fc93b85..6cc67eb6ab 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -4,8 +4,11 @@ name: Build Python Wheels
 
 on:
   pull_request:
-  # Running on PRs is enough
-  # push:
+  # Running on PRs and main branch only
+  # pull requests should be able to access cache from main branch
+  push:
+    branches:
+      - master
   release:
     types: [published]
 
@@ -49,7 +52,7 @@ jobs:
           HOST_CCACHE_DIR="$(ccache -k cache_dir)"
           mkdir -p $HOST_CCACHE_DIR
       - name: Build wheels  # check https://cibuildwheel.readthedocs.io/en/stable/setup/#github-actions
-        uses: pypa/cibuildwheel@v2.12.3
+        uses: pypa/cibuildwheel@v2.13.0
         # to supply options, put them in 'env', like:
         # env:
         #   CIBW_SOME_OPTION: value
@@ -71,15 +74,12 @@ jobs:
         with:
           path: ./wheelhouse/*.whl
 
-# The following was taken from https://cibuildwheel.readthedocs.io/en/stable/deliver-to-pypi/
+  # The following was taken from https://cibuildwheel.readthedocs.io/en/stable/deliver-to-pypi/
   make_sdist:
     name: Make SDist
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
-      with:
-        fetch-depth: 0  # Optional, use if you use setuptools_scm
-        submodules: true  # Optional, use if you have submodules
+    - uses: actions/checkout@v3
 
     - name: Build SDist
       run: pipx run build --sdist
@@ -102,7 +102,7 @@ jobs:
       with:
         user: __token__
         password: ${{ secrets.test_pypi_password }}
-        repository_url: https://test.pypi.org/legacy/
+        repository-url: https://test.pypi.org/legacy/
 
   upload_to_pypi:
     needs: [build, make_sdist]
diff --git a/.github/workflows/cache-maintenance.yml b/.github/workflows/cache-maintenance.yml
new file mode 100644
index 0000000000..ec933b1f1b
--- /dev/null
+++ b/.github/workflows/cache-maintenance.yml
@@ -0,0 +1,35 @@
+name: cleanup caches by a branch
+# https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#force-deleting-cache-entries
+# Caches are very large and must be deleted to prioritize main branch's caches.
+on:
+  pull_request:
+    types:
+      - closed
+
+jobs:
+  cleanup:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v3
+
+      - name: Cleanup
+        run: |
+          gh extension install actions/gh-actions-cache
+
+          REPO=${{ github.repository }}
+          BRANCH="refs/pull/${{ github.event.pull_request.number }}/merge"
+
+          echo "Fetching list of cache key"
+          cacheKeysForPR=$(gh actions-cache list -R $REPO -B $BRANCH | cut -f 1 )
+
+          ## Setting this to not fail the workflow while deleting cache keys.
+          set +e
+          echo "Deleting caches..."
+          for cacheKey in $cacheKeysForPR
+          do
+              gh actions-cache delete $cacheKey -R $REPO -B $BRANCH --confirm
+          done
+          echo "Done"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
\ No newline at end of file
diff --git a/scripts/make_stubs.sh b/scripts/make_stubs.sh
index 1df806a28a..b5fc4a9f9e 100755
--- a/scripts/make_stubs.sh
+++ b/scripts/make_stubs.sh
@@ -1,29 +1,40 @@
 #!/bin/bash -e
 
-# Generates LVS and DRC documentation
+# Generates pyi stubs
 #
 # Run this script from a valid build below the repository root, e.g.
-# <repo-root>/build-debug. It needs to have a "pymod" installation in 
+# <repo-root>/build-debug. It needs to have a "pymod" installation in
 # current directory.
 
 inst=$(realpath $(dirname $0))
-scripts=${inst}/drc_lvs_doc
-ld=$(realpath .)
 
-pymod="$ld/pymod"
+## Detect if klayout pymod libraries are installed
+python=
+for try_python in python python3; do
+  if $try_python -c "import klayout.tl" >/dev/null 2>&1; then
+    python=$try_python
+  fi
+done
 
-export LD_LIBRARY_PATH=$ld
-export PYTHONPATH=$pymod
+if [ "$python" = "" ]; then
+  echo "*** Searching for pymod..."
 
-pymod_src=$ld/../src/pymod
-if ! [ -e $pymod_src ]; then
-  echo "*** ERROR: missing pymod sources ($pymod_src) - did you run the script from the build folder below the source tree?"
-  exit 1
-fi
+  ld=$(realpath .)
+  pymod="$ld/pymod"
 
-if ! [ -e $pymod ]; then
-  echo "*** ERROR: missing pymod folder ($pymod) - did you run the script from the build folder?"
-  exit 1
+  export LD_LIBRARY_PATH=$ld
+  export PYTHONPATH=$pymod
+
+  pymod_src=$ld/../src/pymod
+  if ! [ -e $pymod_src ]; then
+    echo "*** ERROR: missing pymod sources ($pymod_src) - did you run the script from the build folder below the source tree?"
+    exit 1
+  fi
+
+  if ! [ -e $pymod ]; then
+    echo "*** ERROR: missing pymod folder ($pymod) - did you run the script from the build folder?"
+    exit 1
+  fi
 fi
 
 python=
@@ -38,20 +49,21 @@ if [ "$python" = "" ]; then
   exit 1
 fi
 
+pyi_srcdir="$inst/../src/pymod/distutils_src/klayout"
+
 echo "Generating stubs for tl .."
-$python $inst/stubgen.py tl >$pymod_src/distutils_src/klayout/tlcore.pyi
+$python $inst/stubgen.py tl >$pyi_srcdir/tlcore.pyi
 
 echo "Generating stubs for db .."
-$python $inst/stubgen.py db tl >$pymod_src/distutils_src/klayout/dbcore.pyi
+$python $inst/stubgen.py db tl >$pyi_srcdir/dbcore.pyi
 
 echo "Generating stubs for rdb .."
-$python $inst/stubgen.py rdb tl,db >$pymod_src/distutils_src/klayout/rdbcore.pyi
+$python $inst/stubgen.py rdb tl,db >$pyi_srcdir/rdbcore.pyi
 
 echo "Generating stubs for lay .."
-$python $inst/stubgen.py lay tl,db,rdb >$pymod_src/distutils_src/klayout/laycore.pyi
+$python $inst/stubgen.py lay tl,db,rdb >$pyi_srcdir/laycore.pyi
 
 echo "Generating stubs for lib .."
-$python $inst/stubgen.py lib tl,db >$pymod_src/distutils_src/klayout/libcore.pyi
+$python $inst/stubgen.py lib tl,db >$pyi_srcdir/libcore.pyi
 
 echo "Done."
-