diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index b35710b..ce86a0a 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -18,8 +18,8 @@ build:
     - libxcb-xfixes0
   jobs:
     pre_install:
-      # Development builds may require a Sigima version not yet released on PyPI
-      - "python scripts/rtd_install_sigima.py"
+      # Development builds may require dependency versions not yet released on PyPI
+      - "python scripts/rtd_install_dev_deps.py"
     pre_build:
       # Start Xvfb before building docs
       - "Xvfb :99 -screen 0 1024x768x24 > /dev/null 2>&1 &"
diff --git a/scripts/rtd_install_dev_deps.py b/scripts/rtd_install_dev_deps.py
new file mode 100644
index 0000000..91cedf1
--- /dev/null
+++ b/scripts/rtd_install_dev_deps.py
@@ -0,0 +1,140 @@
+# -*- coding: utf-8 -*-
+"""
+Install development versions of dependencies for Read the Docs builds.
+
+This project is developed alongside other PlotPyStack and DataLab Platform
+projects: development branches and pull requests may require dependency versions
+which are not yet published on PyPI, so installing the documentation requirements
+from PyPI alone would fail.
+
+This script mirrors the GitHub Actions test workflows:
+
+- tag builds and release branches: nothing is done, dependencies are installed
+  from PyPI by the regular ``python.install`` step;
+- other branches and pull requests: the dependencies listed in
+  ``DEV_DEPENDENCIES`` are installed from GitHub. The regular ``python.install``
+  step then keeps these versions as they already satisfy the project
+  requirements.
+
+It is intended to be run as a ``build.jobs.pre_install`` step and only relies on
+the standard library and ``git``.
+
+The same script is used by several projects: only the project-specific settings
+below differ between copies.
+"""
+
+from __future__ import annotations
+
+import os
+import subprocess
+import sys
+
+# ---- Project-specific settings ----------------------------------------------
+PROJECT_REPO = "https://github.com/DataLab-Platform/SigimaX.git"
+#: Placeholder for the name of the branch being built
+SAME_BRANCH = "{branch}"
+#: Dependencies to install from GitHub for development builds:
+#: package name -> (repository URL, candidate branches, first existing one is used)
+DEV_DEPENDENCIES = {
+    "PythonQwt": ("https://github.com/PlotPyStack/PythonQwt.git", ("master",)),
+    "guidata": ("https://github.com/PlotPyStack/guidata.git", ("develop",)),
+    "PlotPy": ("https://github.com/PlotPyStack/PlotPy.git", ("develop",)),
+    "Sigima": (
+        "https://github.com/DataLab-Platform/Sigima.git",
+        (SAME_BRANCH, "develop"),
+    ),
+}
+# -----------------------------------------------------------------------------
+
+RELEASE_BRANCHES = ("main", "master", "release")
+
+
+def get_remote_branches(url: str) -> dict[str, str]:
+    """Return the branches of a remote Git repository.
+
+    Args:
+        url: Remote repository URL
+
+    Returns:
+        Mapping of branch names to the commit hash of their head
+    """
+    output = subprocess.run(
+        ["git", "ls-remote", "--heads", url],
+        capture_output=True,
+        text=True,
+        check=True,
+    ).stdout
+    branches = {}
+    for line in output.splitlines():
+        commit, ref = line.split("\t", 1)
+        branches[ref.removeprefix("refs/heads/")] = commit
+    return branches
+
+
+def get_built_branch() -> str | None:
+    """Return the branch being built, if it can be determined.
+
+    For pull request builds, Read the Docs only provides the pull request number,
+    so the branch is the one of the project repository whose head is the commit
+    being built.
+
+    Returns:
+        Branch name, or None for tag builds and pull requests from forks
+    """
+    version_type = os.environ.get("READTHEDOCS_VERSION_TYPE")
+    if version_type == "branch":
+        return os.environ["READTHEDOCS_GIT_IDENTIFIER"]
+    if version_type == "external":
+        commit = os.environ["READTHEDOCS_GIT_COMMIT_HASH"]
+        for branch, head in get_remote_branches(PROJECT_REPO).items():
+            if head == commit:
+                return branch
+    return None
+
+
+def select_branch(url: str, candidates: tuple[str, ...], built: str | None) -> str:
+    """Return the first candidate branch which exists in a remote repository.
+
+    Args:
+        url: Remote repository URL
+        candidates: Candidate branch names, ``SAME_BRANCH`` standing for the
+         branch being built
+        built: Branch being built, or None if unknown
+
+    Returns:
+        Selected branch name
+    """
+    names = [built if name == SAME_BRANCH else name for name in candidates]
+    existing = get_remote_branches(url)
+    for name in names:
+        if name is not None and name in existing:
+            return name
+    raise SystemExit(f"None of the branches {names} exists in {url}")
+
+
+def main() -> None:
+    """Install dependencies from GitHub for development builds."""
+    version_type = os.environ.get("READTHEDOCS_VERSION_TYPE")
+    if version_type not in ("branch", "external"):
+        print(f"Version type {version_type!r}: dependencies installed from PyPI")
+        return
+    built = get_built_branch()
+    if built in RELEASE_BRANCHES:
+        print(f"Branch {built!r}: dependencies installed from PyPI")
+        return
+    print(f"Development build (branch: {built or 'unknown'})")
+    requirements = []
+    for name, (url, candidates) in DEV_DEPENDENCIES.items():
+        branch = select_branch(url, candidates, built)
+        print(f"  {name}: {branch!r} branch")
+        requirements.append(f"{name} @ git+{url}@{branch}")
+    # Single pip call, so that dependencies between these packages are resolved
+    # against their development versions rather than against PyPI releases
+    subprocess.run(
+        [sys.executable, "-m", "pip", "install", "--no-cache-dir", *requirements],
+        check=True,
+    )
+
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/rtd_install_sigima.py b/scripts/rtd_install_sigima.py
deleted file mode 100644
index 2f76be8..0000000
--- a/scripts/rtd_install_sigima.py
+++ /dev/null
@@ -1,106 +0,0 @@
-# -*- coding: utf-8 -*-
-"""
-Install the development version of Sigima for Read the Docs builds.
-
-SigimaX is developed alongside Sigima: development branches and pull requests
-may require a Sigima version which is not yet published on PyPI, so installing
-``sigimax[doc]`` from PyPI alone would fail.
-
-This script mirrors the GitHub Actions test workflows:
-
-- tag builds and the ``main`` branch: nothing is done, Sigima is installed from
-  PyPI by the regular ``python.install`` step;
-- other branches and pull requests: Sigima is installed from the GitHub branch
-  with the same name as the SigimaX branch if it exists, otherwise from
-  ``develop``. The regular ``python.install`` step then keeps this version as it
-  already satisfies SigimaX requirements.
-
-It is intended to be run as a ``build.jobs.pre_install`` step and only relies
-on the standard library and ``git``.
-"""
-
-from __future__ import annotations
-
-import os
-import subprocess
-import sys
-
-SIGIMA_REPO = "https://github.com/DataLab-Platform/Sigima.git"
-SIGIMAX_REPO = "https://github.com/DataLab-Platform/SigimaX.git"
-DEFAULT_BRANCH = "develop"
-RELEASE_BRANCH = "main"
-
-
-def get_remote_branches(url: str) -> dict[str, str]:
-    """Return the branches of a remote Git repository.
-
-    Args:
-        url: Remote repository URL
-
-    Returns:
-        Mapping of branch names to the commit hash of their head
-    """
-    output = subprocess.run(
-        ["git", "ls-remote", "--heads", url],
-        capture_output=True,
-        text=True,
-        check=True,
-    ).stdout
-    branches = {}
-    for line in output.splitlines():
-        commit, ref = line.split("\t", 1)
-        branches[ref.removeprefix("refs/heads/")] = commit
-    return branches
-
-
-def get_sigimax_branch() -> str | None:
-    """Return the SigimaX branch being built, if it can be determined.
-
-    For pull request builds, Read the Docs only provides the pull request number,
-    so the branch is the one of the SigimaX repository whose head is the commit
-    being built.
-
-    Returns:
-        Branch name, or None for tag builds and pull requests from forks
-    """
-    version_type = os.environ.get("READTHEDOCS_VERSION_TYPE")
-    if version_type == "branch":
-        return os.environ["READTHEDOCS_GIT_IDENTIFIER"]
-    if version_type == "external":
-        commit = os.environ["READTHEDOCS_GIT_COMMIT_HASH"]
-        for branch, head in get_remote_branches(SIGIMAX_REPO).items():
-            if head == commit:
-                return branch
-    return None
-
-
-def main() -> None:
-    """Install Sigima from GitHub for development builds."""
-    version_type = os.environ.get("READTHEDOCS_VERSION_TYPE")
-    if version_type not in ("branch", "external"):
-        print(f"Version type {version_type!r}: Sigima will be installed from PyPI")
-        return
-    sigimax_branch = get_sigimax_branch()
-    if sigimax_branch == RELEASE_BRANCH:
-        print(f"Branch {RELEASE_BRANCH!r}: Sigima will be installed from PyPI")
-        return
-    if sigimax_branch in get_remote_branches(SIGIMA_REPO):
-        sigima_branch = sigimax_branch
-    else:
-        sigima_branch = DEFAULT_BRANCH
-    print(f"SigimaX branch: {sigimax_branch!r} -> Sigima branch: {sigima_branch!r}")
-    subprocess.run(
-        [
-            sys.executable,
-            "-m",
-            "pip",
-            "install",
-            "--no-cache-dir",
-            f"sigima @ git+{SIGIMA_REPO}@{sigima_branch}",
-        ],
-        check=True,
-    )
-
-
-if __name__ == "__main__":
-    main()