diff --git a/.github/workflows/mamba.yml b/.github/workflows/mamba.yml
index 27b5a56..748c0c1 100644
--- a/.github/workflows/mamba.yml
+++ b/.github/workflows/mamba.yml
@@ -1,65 +1,65 @@
-name: Mamba tests
+# name: Mamba tests
 
-on:
-  push:
-    branches: [master]
-  pull_request:
+# on:
+#   push:
+#     branches: [master]
+#   pull_request:
 
-jobs:
-  mamba_test:
-    strategy:
-      matrix:
-        os: [ubuntu-latest, windows-latest]
+# jobs:
+#   mamba_test:
+#     strategy:
+#       matrix:
+#         os: [ubuntu-latest, windows-latest]
 
-    runs-on: ${{ matrix.os }}
+#     runs-on: ${{ matrix.os }}
 
-    steps:
-    - uses: actions/checkout@v2
+#     steps:
+#     - uses: actions/checkout@v2
 
-    - name: Set up Python 3.7
-      uses: actions/setup-python@v2
-      with:
-        python-version: 3.7
+#     - name: Set up Python 3.7
+#       uses: actions/setup-python@v2
+#       with:
+#         python-version: 3.7
 
-    - name: Upgrade pip
-      run: |
-        python3 -m pip install --upgrade pipenv
+#     - name: Upgrade pip
+#       run: |
+#         python3 -m pip install --upgrade pipenv
 
-    # Pipenv doesn't support specifying global options.  See:
-    #
-    # https://github.com/pypa/pipenv/issues/2208
-    #
-    # We want to make sure that we're testing pure python dulwich,
-    # since that's what the users will be using.
-    #
-    # We only want to install dulwich via the `-r requirements.txt`
-    # method, since the presence of any non-default option causes pip
-    # to avoid using wheels for all the other dependencies, which
-    # slows down the build considerably (and breaks it on Windows).  I
-    # don't think that any of our other current dependencies might
-    # potentially use binary wheels, so in this case using wheels is
-    # probably safe.  (Besides, AFAIK we didn't have any issues
-    # specifically caused by a dependency other than dulwich (see
-    # #138, so testing the other dependencies isn't a focus.)
-    #
-    # Unfortunately, I didn't manage to get process substitution
-    # (`<()`) to work, within GitHub actions, so I'm writing
-    # requirements.txt to a file.
-    - name: Write dulwich version to requirements.txt
-      shell: bash
-      run: |
-        pipenv lock -r | sed -nE 's/(^dulwich==.+$)/\1 --global-option=--pure/p' > requirements.txt
+#     # Pipenv doesn't support specifying global options.  See:
+#     #
+#     # https://github.com/pypa/pipenv/issues/2208
+#     #
+#     # We want to make sure that we're testing pure python dulwich,
+#     # since that's what the users will be using.
+#     #
+#     # We only want to install dulwich via the `-r requirements.txt`
+#     # method, since the presence of any non-default option causes pip
+#     # to avoid using wheels for all the other dependencies, which
+#     # slows down the build considerably (and breaks it on Windows).  I
+#     # don't think that any of our other current dependencies might
+#     # potentially use binary wheels, so in this case using wheels is
+#     # probably safe.  (Besides, AFAIK we didn't have any issues
+#     # specifically caused by a dependency other than dulwich (see
+#     # #138, so testing the other dependencies isn't a focus.)
+#     #
+#     # Unfortunately, I didn't manage to get process substitution
+#     # (`<()`) to work, within GitHub actions, so I'm writing
+#     # requirements.txt to a file.
+#     - name: Write dulwich version to requirements.txt
+#       shell: bash
+#       run: |
+#         pipenv lock -r | sed -nE 's/(^dulwich==.+$)/\1 --global-option=--pure/p' > requirements.txt
 
-    - name: Install pure dulwich from requirements.txt
-      run: |
-        pipenv run pip install -r requirements.txt
+#     - name: Install pure dulwich from requirements.txt
+#       run: |
+#         pipenv run pip install -r requirements.txt
 
-    - name: Install all other dependencies
-      shell: bash
-      run: |
-        pipenv install --dev
+#     - name: Install all other dependencies
+#       shell: bash
+#       run: |
+#         pipenv install --dev
 
-    # TODO Run each test separately?  (See: #145.)
-    - name: Run tests
-      run: |
-        pipenv run mamba ./
+#     # TODO Run each test separately?  (See: #145.)
+#     - name: Run tests
+#       run: |
+#         pipenv run mamba ./