diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 96a2b68..c00bd2c 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -21,6 +21,7 @@ jobs:
           - { python: "3.11", os: "ubuntu-latest", session: "mypy" }
           - { python: "3.11", os: "ubuntu-latest", session: "tests" }
           - { python: "3.11", os: "ubuntu-latest", session: "xdoctest" }
+          - { python: "3.12", os: "ubuntu-latest", session: "docs-build" }
           - { python: "3.12", os: "windows-latest", session: "pre-commit" }
           - { python: "3.12", os: "windows-latest", session: "safety" }
           - { python: "3.12", os: "windows-latest", session: "mypy" }
@@ -45,21 +46,6 @@ jobs:
       - name: Check out the repository
         uses: actions/checkout@v4
 
-      - name: Set up R if on MacOS
-        if: matrix.os == 'macos-latest'
-        uses: r-lib/actions/setup-r@v2
-
-      - name: Install remotes R package if on MacOS
-        if: matrix.os == 'macos-latest'
-        uses: r-lib/actions/setup-r-dependencies@v2
-        with:
-          packages: remotes
-
-      - name: Install kinfitr if on MacOS
-        if: matrix.os == 'macos-latest'
-        run: |
-          Rscript -e "remotes::install_url('https://github.com/mathesong/kinfitr/archive/refs/tags/v0.8.0.tar.gz')"
-
       - name: Set up Python ${{ matrix.python }}
         uses: actions/setup-python@v5
         with:
@@ -127,14 +113,14 @@ jobs:
           include-hidden-files: true
 
       - name: Upload documentation
-        if: matrix.session == 'docs-build' && matrix.os == 'macos-latest'
+        if: matrix.session == 'docs-build'
         uses: actions/upload-artifact@v3
         with:
           name: docs
           path: docs/_build
 
   coverage:
-    runs-on: macos-latest
+    runs-on: ubuntu-latest
     needs: tests
     steps:
       - name: Check out the repository
diff --git a/noxfile.py b/noxfile.py
index dd29154..c568c6d 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -157,10 +157,7 @@ def safety(session: Session) -> None:
 def mypy(session: Session) -> None:
     """Type-check using mypy."""
     args = session.posargs or ["src", "tests", "docs/conf.py"]
-    if os.getenv("GITHUB_ACTIONS") and os.name != "nt":
-        session.install(".[kinfitr]")
-    else:
-        session.install(".")
+    session.install(".")
     session.install("mypy", "pytest", "pytest-mock", "requests", "types-requests")
     session.run("mypy", *args)
     if not session.posargs:
@@ -170,10 +167,7 @@ def mypy(session: Session) -> None:
 @session(python=python_versions)
 def tests(session: Session) -> None:
     """Run the test suite."""
-    if os.getenv("GITHUB_ACTIONS") and os.name != "nt":
-        session.install(".[kinfitr]")
-    else:
-        session.install(".")
+    session.install(".")
     session.install("coverage[toml]", "pytest", "pytest-mock", "pygments", "requests")
     try:
         session.run("coverage", "run", "-p", "-m", "pytest", *session.posargs)
@@ -198,10 +192,7 @@ def coverage(session: Session) -> None:
 @session(python=python_versions[0])
 def typeguard(session: Session) -> None:
     """Runtime type checking using Typeguard."""
-    if os.getenv("GITHUB_ACTIONS") and os.name != "nt":
-        session.install(".[kinfitr]")
-    else:
-        session.install(".")
+    session.install(".")
     session.install("pytest", "pytest-mock", "typeguard", "pygments", "requests")
     session.run("pytest", f"--typeguard-packages={package}", *session.posargs)
 
@@ -216,10 +207,7 @@ def xdoctest(session: Session) -> None:
         if "FORCE_COLOR" in os.environ:
             args.append("--colored=1")
 
-    if os.getenv("GITHUB_ACTIONS") and os.name != "nt":
-        session.install(".[kinfitr]")
-    else:
-        session.install(".")
+    session.install(".")
     session.install("xdoctest[colors]")
     session.run("python", "-m", "xdoctest", *args)
 
@@ -231,10 +219,7 @@ def docs_build(session: Session) -> None:
     if not session.posargs and "FORCE_COLOR" in os.environ:
         args.insert(0, "--color")
 
-    if os.getenv("GITHUB_ACTIONS") and os.name != "nt":
-        session.install(".[kinfitr]")
-    else:
-        session.install(".")
+    session.install(".")
     session.install("sphinx-click", "furo", "myst_nb", "matplotlib", "nilearn")
 
     build_dir = Path("docs", "_build")
@@ -252,10 +237,7 @@ def docs_build(session: Session) -> None:
 def docs(session: Session) -> None:
     """Build and serve the documentation with live reloading on file changes."""
     args = session.posargs or ["--open-browser", "docs", "docs/_build"]
-    if os.getenv("GITHUB_ACTIONS") and os.name != "nt":
-        session.install(".[kinfitr]")
-    else:
-        session.install(".")
+    session.install(".")
     session.install(
         "sphinx-autobuild", "sphinx-click", "furo", "myst_nb", "matplotlib", "nilearn"
     )