diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000..8dd3cb3803
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "build-aux/req2flatpak"]
+	path = build-aux/req2flatpak
+	url = https://github.com/johannesjh/req2flatpak.git
diff --git a/bottles/backend/wine/executor.py b/bottles/backend/wine/executor.py
index dc8daeb3f4..d0142abb48 100644
--- a/bottles/backend/wine/executor.py
+++ b/bottles/backend/wine/executor.py
@@ -74,8 +74,8 @@ def __init__(
         env_dll_overrides = []
 
         if (soundfont_path := midi_soundfont) not in (None, ""):
-            # FluidSynth is bounded to Executor object as a member
-            # to control the MIDI server's lifetime (deleted when zero references)
+            # FluidSynth instance is bound to WineExecutor as a member to control
+            # the former's lifetime (deleted when no more references from executors)
             self.fluidsynth = FluidSynth.find_or_create(soundfont_path)
             self.fluidsynth.register_as_current(config)
 
diff --git a/build-aux/com.usebottles.bottles.Devel.json b/build-aux/com.usebottles.bottles.Devel.json
index 326c23d365..8fcf441952 100644
--- a/build-aux/com.usebottles.bottles.Devel.json
+++ b/build-aux/com.usebottles.bottles.Devel.json
@@ -80,7 +80,7 @@
         "mkdir -p /app/share/vulkan/implicit_layer.d/"
     ],
     "modules": [
-        "com.usebottles.bottles.pypi-deps.yaml",
+        "pypi-deps.yaml",
         {
             "name": "vmtouch",
             "buildsystem": "simple",
diff --git a/build-aux/flatpak-pip-generator.py b/build-aux/flatpak-pip-generator.py
deleted file mode 100644
index e3ff138572..0000000000
--- a/build-aux/flatpak-pip-generator.py
+++ /dev/null
@@ -1,523 +0,0 @@
-#!/usr/bin/env python3
-# original:
-# https://github.com/flatpak/flatpak-builder-tools/blob/67455d214028f1562edf4fa4bcef8ba9d2617d23/pip/flatpak-pip-generator
-# but modified with:
-# - will use arch-dependent whl directly
-# - will still install packages if they already exist in org.freedesktop.Sdk
-
-__license__ = "MIT"
-
-import argparse
-import hashlib
-import json
-import os
-import shutil
-import subprocess
-import sys
-import tempfile
-import urllib.request
-from collections import OrderedDict
-
-try:
-    import requirements
-except ImportError:
-    exit('Requirements modules is not installed. Run "pip install requirements-parser"')
-
-parser = argparse.ArgumentParser()
-parser.add_argument("packages", nargs="*")
-parser.add_argument(
-    "--python2", action="store_true", help="Look for a Python 2 package"
-)
-parser.add_argument(
-    "--cleanup", choices=["scripts", "all"], help="Select what to clean up after build"
-)
-parser.add_argument("--requirements-file", "-r", help="Specify requirements.txt file")
-parser.add_argument(
-    "--build-only",
-    action="store_const",
-    dest="cleanup",
-    const="all",
-    help="Clean up all files after build",
-)
-parser.add_argument(
-    "--build-isolation",
-    action="store_true",
-    default=False,
-    help=(
-        "Do not disable build isolation. "
-        "Mostly useful on pip that does't "
-        "support the feature."
-    ),
-)
-parser.add_argument(
-    "--ignore-installed",
-    type=lambda s: s.split(","),
-    default="",
-    help="Comma-separated list of package names for which pip "
-    "should ignore already installed packages. Useful when "
-    "the package is installed in the SDK but not in the "
-    "runtime.",
-)
-parser.add_argument(
-    "--checker-data",
-    action="store_true",
-    help='Include x-checker-data in output for the "Flatpak External Data Checker"',
-)
-parser.add_argument("--output", "-o", help="Specify output file name")
-parser.add_argument(
-    "--runtime",
-    help="Specify a flatpak to run pip inside of a sandbox, ensures python version compatibility",
-)
-parser.add_argument(
-    "--yaml", action="store_true", help="Use YAML as output format instead of JSON"
-)
-opts = parser.parse_args()
-
-if opts.yaml:
-    try:
-        import yaml
-    except ImportError:
-        exit('PyYAML modules is not installed. Run "pip install PyYAML"')
-
-
-def get_pypi_url(name: str, filename: str) -> str:
-    url = "https://pypi.org/pypi/{}/json".format(name)
-    print("Extracting download url for", name)
-    with urllib.request.urlopen(url) as response:
-        body = json.loads(response.read().decode("utf-8"))
-        for release in body["releases"].values():
-            for source in release:
-                if source["filename"] == filename:
-                    return source["url"]
-        raise Exception("Failed to extract url from {}".format(url))
-
-
-def get_tar_package_url_pypi(name: str, version: str) -> str:
-    url = "https://pypi.org/pypi/{}/{}/json".format(name, version)
-    with urllib.request.urlopen(url) as response:
-        body = json.loads(response.read().decode("utf-8"))
-        for ext in ["bz2", "gz", "xz", "zip"]:
-            for source in body["urls"]:
-                if source["url"].endswith(ext):
-                    return source["url"]
-        err = "Failed to get {}-{} source from {}".format(name, version, url)
-        raise Exception(err)
-
-
-def get_package_name(filename: str) -> str:
-    if filename.endswith(("bz2", "gz", "xz", "zip")):
-        segments = filename.split("-")
-        if len(segments) == 2:
-            return segments[0]
-        return "-".join(segments[: len(segments) - 1])
-    elif filename.endswith("whl"):
-        segments = filename.split("-")
-        if len(segments) == 5:
-            return segments[0]
-        candidate = segments[: len(segments) - 4]
-        # Some packages list the version number twice
-        # e.g. PyQt5-5.15.0-5.15.0-cp35.cp36.cp37.cp38-abi3-manylinux2014_x86_64.whl
-        if candidate[-1] == segments[len(segments) - 4]:
-            return "-".join(candidate[:-1])
-        return "-".join(candidate)
-    else:
-        raise Exception(
-            "Downloaded filename: {} does not end with bz2, gz, xz, zip, or whl".format(
-                filename
-            )
-        )
-
-
-def get_file_version(filename: str) -> str:
-    name = get_package_name(filename)
-    segments = filename.split(name + "-")
-    version = segments[1].split("-")[0]
-    for ext in ["tar.gz", "whl", "tar.xz", "tar.gz", "tar.bz2", "zip"]:
-        version = version.replace("." + ext, "")
-    return version
-
-
-def get_file_hash(filename: str) -> str:
-    sha = hashlib.sha256()
-    print("Generating hash for", filename.split("/")[-1])
-    with open(filename, "rb") as f:
-        while True:
-            data = f.read(1024 * 1024 * 32)
-            if not data:
-                break
-            sha.update(data)
-        return sha.hexdigest()
-
-
-def download_tar_pypi(url: str, tempdir: str) -> None:
-    with urllib.request.urlopen(url) as response:
-        file_path = os.path.join(tempdir, url.split("/")[-1])
-        with open(file_path, "x+b") as tar_file:
-            shutil.copyfileobj(response, tar_file)
-
-
-def parse_continuation_lines(fin):
-    for line in fin:
-        line = line.rstrip("\n")
-        while line.endswith("\\"):
-            try:
-                line = line[:-1] + next(fin).rstrip("\n")
-            except StopIteration:
-                exit(
-                    'Requirements have a wrong number of line continuation characters "\\"'
-                )
-        yield line
-
-
-def fprint(string: str) -> None:
-    separator = "=" * 72  # Same as `flatpak-builder`
-    print(separator)
-    print(string)
-    print(separator)
-
-
-packages = []
-if opts.requirements_file:
-    requirements_file = os.path.expanduser(opts.requirements_file)
-    try:
-        with open(requirements_file, "r") as req_file:
-            reqs = parse_continuation_lines(req_file)
-            reqs_as_str = "\n".join([r.split("--hash")[0] for r in reqs])
-            packages = list(requirements.parse(reqs_as_str))
-    except FileNotFoundError:
-        pass
-
-elif opts.packages:
-    packages = list(requirements.parse("\n".join(opts.packages)))
-    with tempfile.NamedTemporaryFile(
-        "w", delete=False, prefix="requirements."
-    ) as req_file:
-        req_file.write("\n".join(opts.packages))
-        requirements_file = req_file.name
-else:
-    exit("Please specifiy either packages or requirements file argument")
-
-for i in packages:
-    if i["name"].lower().startswith("pyqt"):
-        print("PyQt packages are not supported by flapak-pip-generator")
-        print("However, there is a BaseApp for PyQt available, that you should use")
-        print(
-            "Visit https://github.com/flathub/com.riverbankcomputing.PyQt.BaseApp for more information"
-        )
-        sys.exit(0)
-
-with open(requirements_file, "r") as req_file:
-    use_hash = "--hash=" in req_file.read()
-
-python_version = "2" if opts.python2 else "3"
-if opts.python2:
-    pip_executable = "pip2"
-else:
-    pip_executable = "pip3"
-
-if opts.runtime:
-    flatpak_cmd = [
-        "flatpak",
-        "--devel",
-        "--share=network",
-        "--filesystem=/tmp",
-        "--command={}".format(pip_executable),
-        "run",
-        opts.runtime,
-    ]
-    if opts.requirements_file:
-        requirements_file = os.path.expanduser(opts.requirements_file)
-        if os.path.exists(requirements_file):
-            prefix = os.path.realpath(requirements_file)
-            flag = "--filesystem={}".format(prefix)
-            flatpak_cmd.insert(1, flag)
-else:
-    flatpak_cmd = [pip_executable]
-
-if opts.output:
-    output_package = opts.output
-elif opts.requirements_file:
-    output_package = "python{}-{}".format(
-        python_version,
-        os.path.basename(opts.requirements_file).replace(".txt", ""),
-    )
-elif len(packages) == 1:
-    output_package = "python{}-{}".format(
-        python_version,
-        packages[0].name,
-    )
-else:
-    output_package = "python{}-modules".format(python_version)
-if opts.yaml:
-    output_filename = output_package + ".yaml"
-else:
-    output_filename = output_package + ".json"
-
-modules = []
-vcs_modules = []
-sources = {}
-
-tempdir_prefix = "pip-generator-{}".format(os.path.basename(output_package))
-with tempfile.TemporaryDirectory(prefix=tempdir_prefix) as tempdir:
-    pip_download = flatpak_cmd + [
-        "download",
-        "--exists-action=i",
-        "--dest",
-        tempdir,
-        "-r",
-        requirements_file,
-    ]
-    if use_hash:
-        pip_download.append("--require-hashes")
-
-    fprint("Downloading sources")
-    cmd = " ".join(pip_download)
-    print('Running: "{}"'.format(cmd))
-    try:
-        subprocess.run(pip_download, check=True)
-    except subprocess.CalledProcessError:
-        print("Failed to download")
-        print("Please fix the module manually in the generated file")
-
-    if not opts.requirements_file:
-        try:
-            os.remove(requirements_file)
-        except FileNotFoundError:
-            pass
-
-    fprint("Downloading arch independent packages")
-    for filename in os.listdir(tempdir):
-        if not filename.endswith(
-            ("bz2", "whl", "gz", "xz", "zip")
-        ):  # modified 'any.whl' to 'whl'
-            version = get_file_version(filename)
-            name = get_package_name(filename)
-            url = get_tar_package_url_pypi(name, version)
-            print("Deleting", filename)
-            try:
-                os.remove(os.path.join(tempdir, filename))
-            except FileNotFoundError:
-                pass
-            print("Downloading {}".format(url))
-            download_tar_pypi(url, tempdir)
-
-    files = {get_package_name(f): [] for f in os.listdir(tempdir)}
-
-    for filename in os.listdir(tempdir):
-        name = get_package_name(filename)
-        files[name].append(filename)
-
-    # Delete redundant sources, for vcs sources
-    for name in files:
-        if len(files[name]) > 1:
-            zip_source = False
-            for f in files[name]:
-                if f.endswith(".zip"):
-                    zip_source = True
-            if zip_source:
-                for f in files[name]:
-                    if not f.endswith(".zip"):
-                        try:
-                            os.remove(os.path.join(tempdir, f))
-                        except FileNotFoundError:
-                            pass
-
-    vcs_packages = {
-        x.name: {"vcs": x.vcs, "revision": x.revision, "uri": x.uri}
-        for x in packages
-        if x.vcs
-    }
-
-    fprint("Obtaining hashes and urls")
-    for filename in os.listdir(tempdir):
-        name = get_package_name(filename)
-        sha256 = get_file_hash(os.path.join(tempdir, filename))
-
-        if name in vcs_packages:
-            uri = vcs_packages[name]["uri"]
-            revision = vcs_packages[name]["revision"]
-            vcs = vcs_packages[name]["vcs"]
-            url = "https://" + uri.split("://", 1)[1]
-            s = "commit"
-            if vcs == "svn":
-                s = "revision"
-            source = OrderedDict(
-                [
-                    ("type", vcs),
-                    ("url", url),
-                    (s, revision),
-                ]
-            )
-            is_vcs = True
-        else:
-            url = get_pypi_url(name, filename)
-            source = OrderedDict([("type", "file"), ("url", url), ("sha256", sha256)])
-            if opts.checker_data:
-                source["x-checker-data"] = {"type": "pypi", "name": name}
-                if url.endswith(".whl"):
-                    source["x-checker-data"]["packagetype"] = "bdist_wheel"
-            is_vcs = False
-        sources[name] = {"source": source, "vcs": is_vcs}
-
-# Python3 packages that come as part of org.freedesktop.Sdk.
-system_packages = [
-    "cython",
-    "easy_install",
-    "mako",
-    "markdown",
-    "meson",
-    "pip",
-    "pygments",
-    "setuptools",
-    "six",
-    "wheel",
-]
-
-fprint("Generating dependencies")
-for package in packages:
-    if package.name is None:
-        print(
-            "Warning: skipping invalid requirement specification {} because it is missing a name".format(
-                package.line
-            ),
-            file=sys.stderr,
-        )
-        print(
-            "Append #egg=<pkgname> to the end of the requirement line to fix",
-            file=sys.stderr,
-        )
-        continue
-    elif package.name.casefold() in system_packages:
-        # modified
-        print(f"{package.name} is in system_packages. Proceed anyway.")
-
-    if len(package.extras) > 0:
-        extras = "[" + ",".join(extra for extra in package.extras) + "]"
-    else:
-        extras = ""
-
-    version_list = [x[0] + x[1] for x in package.specs]
-    version = ",".join(version_list)
-
-    if package.vcs:
-        revision = ""
-        if package.revision:
-            revision = "@" + package.revision
-        pkg = package.uri + revision + "#egg=" + package.name
-    else:
-        pkg = package.name + extras + version
-
-    dependencies = []
-    # Downloads the package again to list dependencies
-
-    tempdir_prefix = "pip-generator-{}".format(package.name)
-    with tempfile.TemporaryDirectory(
-        prefix="{}-{}".format(tempdir_prefix, package.name)
-    ) as tempdir:
-        pip_download = flatpak_cmd + [
-            "download",
-            "--exists-action=i",
-            "--dest",
-            tempdir,
-        ]
-        try:
-            print("Generating dependencies for {}".format(package.name))
-            subprocess.run(pip_download + [pkg], check=True, stdout=subprocess.DEVNULL)
-            for filename in sorted(os.listdir(tempdir)):
-                dep_name = get_package_name(filename)
-                if dep_name.casefold() in system_packages:
-                    pass  # modified
-                dependencies.append(dep_name)
-
-        except subprocess.CalledProcessError:
-            print("Failed to download {}".format(package.name))
-
-    is_vcs = True if package.vcs else False
-    package_sources = []
-    for dependency in dependencies:
-        if dependency in sources:
-            source = sources[dependency]
-        elif dependency.replace("_", "-") in sources:
-            source = sources[dependency.replace("_", "-")]
-        else:
-            continue
-
-        if not (not source["vcs"] or is_vcs):
-            continue
-
-        package_sources.append(source["source"])
-
-    if package.vcs:
-        name_for_pip = "."
-    else:
-        name_for_pip = pkg
-
-    module_name = "python{}-{}".format(python_version, package.name)
-
-    pip_command = [
-        pip_executable,
-        "install",
-        "--verbose",
-        "--exists-action=i",
-        "--no-index",
-        '--find-links="file://${PWD}"',
-        "--prefix=${FLATPAK_DEST}",
-        '"{}"'.format(name_for_pip),
-    ]
-    if package.name in opts.ignore_installed:
-        pip_command.append("--ignore-installed")
-    if package.name.casefold() in system_packages:  # modified
-        print(f"{package.name} is in system_packages, adding --ignore-installed")
-        pip_command.append("--ignore-installed")
-    if not opts.build_isolation:
-        pip_command.append("--no-build-isolation")
-
-    module = OrderedDict(
-        [
-            ("name", module_name),
-            ("buildsystem", "simple"),
-            ("build-commands", [" ".join(pip_command)]),
-            ("sources", package_sources),
-        ]
-    )
-    if opts.cleanup == "all":
-        module["cleanup"] = ["*"]
-    elif opts.cleanup == "scripts":
-        module["cleanup"] = ["/bin", "/share/man/man1"]
-
-    if package.vcs:
-        vcs_modules.append(module)
-    else:
-        modules.append(module)
-
-modules = vcs_modules + modules
-if len(modules) == 1:
-    pypi_module = modules[0]
-else:
-    pypi_module = {
-        "name": output_package,
-        "buildsystem": "simple",
-        "build-commands": [],
-        "modules": modules,
-    }
-
-print()
-with open(output_filename, "w") as output:
-    if opts.yaml:
-
-        class OrderedDumper(yaml.Dumper):
-            def increase_indent(self, flow=False, indentless=False):
-                return super(OrderedDumper, self).increase_indent(flow, False)
-
-        def dict_representer(dumper, data):
-            return dumper.represent_dict(data.items())
-
-        OrderedDumper.add_representer(OrderedDict, dict_representer)
-
-        output.write(
-            "# Generated with flatpak-pip-generator " + " ".join(sys.argv[1:]) + "\n"
-        )
-        yaml.dump(pypi_module, output, Dumper=OrderedDumper)
-    else:
-        output.write(json.dumps(pypi_module, indent=4))
-    print("Output saved to {}".format(output_filename))
diff --git a/build-aux/com.usebottles.bottles.pypi-deps.yaml b/build-aux/pypi-deps.yaml
similarity index 98%
rename from build-aux/com.usebottles.bottles.pypi-deps.yaml
rename to build-aux/pypi-deps.yaml
index 0f51f83114..055b61a6f2 100644
--- a/build-aux/com.usebottles.bottles.pypi-deps.yaml
+++ b/build-aux/pypi-deps.yaml
@@ -1,4 +1,4 @@
-# Generated by req2flatpak.py --requirements-file requirements.txt --yaml --target-platforms 312-x86_64 -o com.usebottles.bottles.pypi-deps.yaml
+# Generated by req2flatpak.py --requirements-file requirements.txt --yaml --target-platforms 312-x86_64 -o build-aux/pypi-deps.yaml
 name: python3-package-installation
 buildsystem: simple
 build-commands:
diff --git a/build-aux/req2flatpak b/build-aux/req2flatpak
new file mode 160000
index 0000000000..2c715eb5cb
--- /dev/null
+++ b/build-aux/req2flatpak
@@ -0,0 +1 @@
+Subproject commit 2c715eb5cb493f606500f2b9c17c0c3675a36454