diff --git a/contrib/mitm-ui/README.md b/contrib/mitm-ui/README.md
deleted file mode 100644
index 1ec8dd4a78..0000000000
--- a/contrib/mitm-ui/README.md
+++ /dev/null
@@ -1,61 +0,0 @@
-# Scripts for PolyGerrit local development against prod using MitmProxy.
-
-## Installation (OSX)
-
-1. Install Docker from http://docker.com
-2. Start the proxy and create a new proxied browser instance
-   ```
-   cd ~/gerrit
-   ~/mitm-gerrit/mitm-serve-app-dev.sh
-   ```
-3. Make sure that the browser uses the proxy provided by the command line,
-   e.g. if you are a Googler check that the BeyondCorp extension uses the
-   "System/Alternative" proxy.
-4. Install MITM certificates
-   - Open http://mitm.it in the proxied browser window
-   - Follow the instructions to install MITM certs
-
-## Usage
-
-### Add or replace a single plugin containing static content
-
-To develop unminified plugin that loads multiple files, use this.
-
-1. Create a new proxied browser window and start mitmproxy via Docker:
-   ```
-   ~/mitm-gerrit/mitm-single-plugin.sh ./path/to/static/plugin.html
-   ```
-2. Open any *.googlesource.com domain in proxied window
-3. plugin.html and ./path/to/static/* will be served
-
-### Add or replace a minified plugin for *.googlesource.com
-
-This flow assumes no additional .html/.js are needed, i.e. the plugin is a single file.
-
-1. Create a new proxied browser window and start mitmproxy via Docker:
-   ```
-   ~/mitm-gerrit/mitm-plugins.sh ./path/to/plugin.html,./maybe/one/more.js
-   ```
-2. Open any *.googlesource.com domain in proxied window
-3. plugin.html and more.js are served
-
-### Force or replace default site theme for *.googlesource.com
-
-1. Create a new proxied browser window and start mitmproxy via Docker:
-   ```
-   ~/mitm-gerrit/mitm-theme.sh ./path/to/theme.html
-   ```
-2. Open any *.googlesource.com domain in proxied window
-3. Default site themes are enabled.
-4. Local `theme.html` content replaces `/static/gerrit-theme.html`
-5. `/static/*` URLs are served from local theme directory, i.e. `./path/to/`
-
-### Serve uncompiled PolyGerrit
-
-1. Create a new proxied browser window and start mitmproxy via Docker:
-   ```
-   cd ~/gerrit
-   ~/mitm-gerrit/mitm-serve-app-dev.sh
-   ```
-2. Open any *.googlesource.com domain in proxied window
-3. Instead of prod UI (gr-app.html, gr-app.js), local source files will be served
diff --git a/contrib/mitm-ui/add-header.py b/contrib/mitm-ui/add-header.py
deleted file mode 100644
index f9b2b121e0..0000000000
--- a/contrib/mitm-ui/add-header.py
+++ /dev/null
@@ -1,5 +0,0 @@
-# mitmdump -s add-header.py
-def response(flow):
-    if flow.request.host == 'gerrit-review.googlesource.com' and flow.request.path == "/c/92000?1":
-        #flow.response.headers['any'] = '<meta.rdf>; rel=meta'
-        flow.response.headers['Link'] = '</changes/98000/detail?O=11640c>;rel="preload";crossorigin;'
diff --git a/contrib/mitm-ui/dev-chrome.sh b/contrib/mitm-ui/dev-chrome.sh
deleted file mode 100755
index adcb296d9b..0000000000
--- a/contrib/mitm-ui/dev-chrome.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/bin/sh
-
-if [[ "$OSTYPE" != "darwin"* ]]; then
-    echo Only works on OSX.
-    exit 1
-fi
-
-/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --remote-debugging-port=9222 --user-data-dir=${HOME}/devchrome --proxy-server="127.0.0.1:8888"
diff --git a/contrib/mitm-ui/force-version.py b/contrib/mitm-ui/force-version.py
deleted file mode 100644
index a69c885b09..0000000000
--- a/contrib/mitm-ui/force-version.py
+++ /dev/null
@@ -1,22 +0,0 @@
-# mitmdump -q -p 8888 -s "force-version.py --version $1"
-# Request URL is not changed, only the response context
-from mitmproxy import http
-import argparse
-import re
-
-class Server:
-    def __init__(self, version):
-        self.version = version
-
-    def request(self, flow: http.HTTPFlow) -> None:
-        if "gr-app." in flow.request.pretty_url:
-            flow.request.url = re.sub(
-                r"polygerrit_ui/([\d.]+)/elements",
-                "polygerrit_ui/" + self.version + "/elements",
-                flow.request.url)
-
-def start():
-    parser = argparse.ArgumentParser()
-    parser.add_argument("--version", type=str, help="Rapid release version, e.g. 432.0")
-    args = parser.parse_args()
-    return Server(args.version)
diff --git a/contrib/mitm-ui/mitm-docker.sh b/contrib/mitm-ui/mitm-docker.sh
deleted file mode 100755
index a1206f71f4..0000000000
--- a/contrib/mitm-ui/mitm-docker.sh
+++ /dev/null
@@ -1,43 +0,0 @@
-#!/bin/sh
-
-extra_volume='/tmp:/tmp'
-
-POSITIONAL=()
-while [[ $# -gt 0 ]]
-do
-key="$1"
-
-case $key in
-    -v|--volume)
-    extra_volume="$2"
-    shift # past argument
-    shift # past value
-    ;;
-    *)    # unknown option
-    POSITIONAL+=("$1") # save it in an array for later
-    shift # past argument
-    ;;
-esac
-done
-set -- "${POSITIONAL[@]}" # restore positional parameters
-
-if [[ -z "$1" ]]; then
-    echo This is a runner for higher-level scripts, e.g. mitm-serve-app-dev.sh
-    echo Alternatively, pass mitmproxy script from the same dir as a parameter, e.g. serve-app-dev.py
-    exit 1
-fi
-
-gerrit_dir=$(pwd)
-mitm_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
-
-CMD="${mitm_dir}/$1"
-
-docker run --rm -it \
-       -v ~/.mitmproxy:/home/mitmproxy/.mitmproxy \
-       -v ${mitm_dir}:${mitm_dir} \
-       -v ${gerrit_dir}:${gerrit_dir} \
-       -v ${gerrit_dir}/bazel-out:${gerrit_dir}/bazel-out \
-       -v ${extra_volume} \
-       -p 8888:8888 \
-       mitmproxy/mitmproxy:2.0.2 \
-       mitmdump -q -p 8888 -s "${CMD}"
diff --git a/contrib/mitm-ui/mitm-plugins.sh b/contrib/mitm-ui/mitm-plugins.sh
deleted file mode 100755
index fc542bb94c..0000000000
--- a/contrib/mitm-ui/mitm-plugins.sh
+++ /dev/null
@@ -1,39 +0,0 @@
-#!/bin/sh
-
-if [[ -z "$1" ]]; then
-    echo This script injects plugins for *.googlesource.com.
-    echo Provide plugin paths, comma-separated, as a parameter.
-    echo This script assumes files do not have dependencies, i.e. minified.
-    exit 1
-fi
-
-realpath() {
-    [[ $1 = /* ]] && echo "$1" || echo "$PWD/${1#./}"
-}
-
-join () {
-  local IFS="$1"
-  shift
-  echo "$*"
-}
-
-plugins=$1
-plugin_paths=()
-for plugin in $(echo ${plugins} | sed "s/,/ /g")
-do
-    plugin_paths+=($(realpath ${plugin}))
-done
-
-absolute_plugin_paths=$(join , "${plugin_paths[@]}")
-
-mitm_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
-
-${mitm_dir}/dev-chrome.sh &
-
-bazel build //polygerrit-ui/app:test_components &
-
-${mitm_dir}/mitm-docker.sh \
-           "serve-app-dev.py \
-           --plugins ${absolute_plugin_paths} \
-           --strip_assets \
-           --components $(pwd)/bazel-bin/polygerrit-ui/app/"
diff --git a/contrib/mitm-ui/mitm-serve-app-dev.sh b/contrib/mitm-ui/mitm-serve-app-dev.sh
deleted file mode 100755
index d4c72cc1c8..0000000000
--- a/contrib/mitm-ui/mitm-serve-app-dev.sh
+++ /dev/null
@@ -1,15 +0,0 @@
-#!/bin/sh
-
-workspace="./WORKSPACE"
-if [[ ! -f ${workspace} ]] || [[ ! $(head -n 1 ${workspace}) == *"gerrit"* ]]; then
-    echo Please change to cloned Gerrit repo from https://gerrit.googlesource.com/gerrit/
-    exit 1
-fi
-
-mitm_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
-
-bazel build //polygerrit-ui/app:test_components &
-
-${mitm_dir}/dev-chrome.sh &
-
-${mitm_dir}/mitm-docker.sh "serve-app-dev.py --app $(pwd)/polygerrit-ui/app/ --components $(pwd)/bazel-bin/polygerrit-ui/app/"
diff --git a/contrib/mitm-ui/mitm-single-plugin.sh b/contrib/mitm-ui/mitm-single-plugin.sh
deleted file mode 100755
index 895822984d..0000000000
--- a/contrib/mitm-ui/mitm-single-plugin.sh
+++ /dev/null
@@ -1,38 +0,0 @@
-#!/bin/sh
-
-if [[ -z "$1" ]]; then
-    echo This script serves one plugin with the rest of static content.
-    echo Provide path to index plugin file, e.g. buildbucket.html for buildbucket plugin
-    exit 1
-fi
-
-realpath() {
-  OURPWD=$PWD
-  cd "$(dirname "$1")"
-  LINK=$(basename "$1")
-  while [ -L "$LINK" ]; do
-      LINK=$(readlink "$LINK")
-      cd "$(dirname "$LINK")"
-      LINK="$(basename "$1")"
-  done
-  REAL_DIR=`pwd -P`
-  RESULT=$REAL_DIR/$LINK
-  cd "$OURPWD"
-  echo "$RESULT"
-}
-
-plugin=$(realpath $1)
-plugin_root=$(dirname ${plugin})
-
-mitm_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
-
-${mitm_dir}/dev-chrome.sh &
-
-bazel build //polygerrit-ui/app:test_components &
-
-${mitm_dir}/mitm-docker.sh -v ${plugin_root}:${plugin_root} \
-           "serve-app-dev.py \
-           --plugins ${plugin} \
-           --strip_assets \
-           --plugin_root ${plugin_root}  \
-           --components $(pwd)/bazel-bin/polygerrit-ui/app/"
diff --git a/contrib/mitm-ui/mitm-theme.sh b/contrib/mitm-ui/mitm-theme.sh
deleted file mode 100755
index 9290235e5e..0000000000
--- a/contrib/mitm-ui/mitm-theme.sh
+++ /dev/null
@@ -1,31 +0,0 @@
-#!/bin/sh
-
-if [[ -z "$1" ]]; then
-    echo This script forces or replaces default site theme on *.googlesource.com
-    echo Provide path to the theme.html as a parameter.
-    exit 1
-fi
-
-realpath() {
-  OURPWD=$PWD
-  cd "$(dirname "$1")"
-  LINK=$(basename "$1")
-  while [ -L "$LINK" ]; do
-      LINK=$(readlink "$LINK")
-      cd "$(dirname "$LINK")"
-      LINK="$(basename "$1")"
-  done
-  REAL_DIR=`pwd -P`
-  RESULT=$REAL_DIR/$LINK
-  cd "$OURPWD"
-  echo "$RESULT"
-}
-
-theme=$(realpath "$1")
-theme_dir=$(dirname "${theme}")
-
-mitm_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
-
-"${mitm_dir}"/dev-chrome.sh &
-
-"${mitm_dir}"/mitm-docker.sh -v "${theme_dir}":"${theme_dir}" "serve-app-dev.py --strip_assets --theme \"${theme}\""
diff --git a/contrib/mitm-ui/serve-app-dev.py b/contrib/mitm-ui/serve-app-dev.py
deleted file mode 100644
index cdf7bfcec2..0000000000
--- a/contrib/mitm-ui/serve-app-dev.py
+++ /dev/null
@@ -1,169 +0,0 @@
-# 1. install and setup mitmproxy v2.0.2: https://mitmproxy.readthedocs.io/en/v2.0.2/install.html
-#   (In case of python versions trouble, use https://www.anaconda.com/)
-# 2. mitmdump -q -s -p 8888 \
-#   "serve-app-dev.py --app /path/to/polygerrit-ui/app/"
-# 3. start Chrome with --proxy-server="127.0.0.1:8888" --user-data-dir=/tmp/devchrome
-# 4. open, say, gerrit-review.googlesource.com. Or chromium-review.googlesource.com. Any.
-# 5. uncompiled source files are served and you can log in, too.
-# 6. enjoy!
-#
-# P.S. For replacing plugins, use --plugins or --plugin_root
-#
-# --plugin takes comma-separated list of plugins to add or replace.
-#
-# Example: Adding a new plugin to the server response:
-# --plugins ~/gerrit-testsite/plugins/myplugin.html
-#
-# Example: Replace all matching plugins with local versions:
-# --plugins ~/gerrit-testsite/plugins/
-# Following files will be served if they exist for /plugins/tricium/static/tricium.html:
-#  ~/gerrit-testsite/plugins/tricium.html
-#  ~/gerrit-testsite/plugins/tricium/static/tricium.html
-#
-# --assets takes assets bundle.html, expecting rest of the assets files to be in the same folder
-#
-# Example:
-#  --assets ~/gerrit-testsite/assets/a3be19f.html
-#
-
-from mitmproxy import http
-from mitmproxy.script import concurrent
-import argparse
-import json
-import mimetypes
-import os.path
-import re
-import zipfile
-
-class Server:
-    def __init__(self, devpath, components, plugins, pluginroot, assets, strip_assets, theme):
-        if devpath:
-            print("Serving app from " + devpath)
-        if components:
-            print("Serving components from " + components)
-        if pluginroot:
-            print("Serving plugins from " + pluginroot)
-        if assets:
-            self.assets_root, self.assets_file = os.path.split(assets)
-            print("Assets: using " + self.assets_file + " from " + self.assets_root)
-        else:
-            self.assets_root = None
-        if plugins:
-            self.plugins = {path.split("/")[-1:][0]: path for path in map(expandpath, plugins.split(","))}
-            for filename, path in self.plugins.items():
-                print("Serving " + filename + " from " + path)
-        else:
-            self.plugins = {}
-        self.devpath = devpath
-        self.components = components
-        self.pluginroot = pluginroot
-        self.strip_assets = strip_assets
-        self.theme = theme
-
-    def readfile(self, path):
-        with open(path, 'rb') as contentfile:
-            return contentfile.read()
-
-@concurrent
-def response(flow: http.HTTPFlow) -> None:
-    if server.strip_assets:
-        assets_bundle = 'googlesource.com/polygerrit_assets'
-        assets_pos = flow.response.text.find(assets_bundle)
-        if assets_pos != -1:
-            t = flow.response.text
-            flow.response.text = t[:t.rfind('<', 0, assets_pos)] + t[t.find('>', assets_pos) + 1:]
-            return
-
-    if server.assets_root:
-        marker = 'webcomponents-lite.js"></script>'
-        pos = flow.response.text.find(marker)
-        if pos != -1:
-            pos += len(marker)
-            flow.response.text = ''.join([
-                flow.response.text[:pos],
-                '<link rel="import" href="/gerrit_assets/123.0/' + server.assets_file + '">',
-                flow.response.text[pos:]
-            ])
-
-        assets_prefix = "/gerrit_assets/123.0/"
-        if flow.request.path.startswith(assets_prefix):
-            assets_file = flow.request.path[len(assets_prefix):]
-            flow.response.content = server.readfile(server.assets_root + '/' + assets_file)
-            flow.response.status_code = 200
-            if assets_file.endswith('.js'):
-                flow.response.headers['Content-type'] = 'text/javascript'
-            return
-    m = re.match(".+polygerrit_ui/\d+\.\d+/(.+)", flow.request.path)
-    pluginmatch = re.match("^/plugins/(.+)", flow.request.path)
-    localfile = ""
-    content = ""
-    if flow.request.path == "/config/server/info":
-        config = json.loads(flow.response.content[5:].decode('utf8'))
-        if server.theme:
-            config['default_theme'] = '/static/gerrit-theme.html'
-        for filename, path in server.plugins.items():
-            pluginname = filename.split(".")[0]
-            payload = config["plugin"]["js_resource_paths" if filename.endswith(".js") else "html_resource_paths"]
-            if list(filter(lambda url: filename in url, payload)):
-                continue
-            payload.append("plugins/" + pluginname + "/static/" + filename)
-        flow.response.content = str.encode(")]}'\n" + json.dumps(config))
-    if m is not None:
-        filepath = m.groups()[0]
-        if (filepath.startswith("bower_components/")):
-            with zipfile.ZipFile(server.components + "test_components.zip") as bower_zip:
-                content = bower_zip.read(filepath)
-        localfile = server.devpath + filepath
-    elif pluginmatch is not None:
-        pluginfile = flow.request.path_components[-1]
-        if server.plugins and pluginfile in server.plugins:
-            if os.path.isfile(server.plugins[pluginfile]):
-                localfile = server.plugins[pluginfile]
-            else:
-                print("Can't find file " + server.plugins[pluginfile] + " for " + flow.request.path)
-        elif server.pluginroot:
-            pluginurl = pluginmatch.groups()[0]
-            if os.path.isfile(server.pluginroot + pluginfile):
-                localfile = server.pluginroot + pluginfile
-            elif os.path.isfile(server.pluginroot + pluginurl):
-                localfile = server.pluginroot + pluginurl
-
-    if server.theme:
-        if flow.request.path.endswith('/gerrit-theme.html'):
-            localfile = server.theme
-        else:
-            match = re.match("^/static(/[\w\.]+)$", flow.request.path)
-            if match is not None:
-                localfile = os.path.dirname(server.theme) + match.group(1)
-
-    if localfile and os.path.isfile(localfile):
-        if pluginmatch is not None:
-            print("Serving " + flow.request.path + " from " + localfile)
-        content = server.readfile(localfile)
-
-    if content:
-        flow.response.content = content
-        flow.response.status_code = 200
-        localtype = mimetypes.guess_type(localfile)
-        if localtype and localtype[0]:
-            flow.response.headers['Content-type'] = localtype[0]
-
-def expandpath(path):
-    return os.path.realpath(os.path.expanduser(path))
-
-parser = argparse.ArgumentParser()
-parser.add_argument("--app", type=str, default="", help="Path to /polygerrit-ui/app/")
-parser.add_argument("--components", type=str, default="", help="Path to test_components.zip")
-parser.add_argument("--plugins", type=str, default="", help="Comma-separated list of plugin files to add/replace")
-parser.add_argument("--plugin_root", type=str, default="", help="Path containing individual plugin files to replace")
-parser.add_argument("--assets", type=str, default="", help="Path containing assets file to import.")
-parser.add_argument("--strip_assets", action="store_true", help="Strip plugin bundles from the response.")
-parser.add_argument("--theme", default="", type=str, help="Path to the default site theme to be used.")
-args = parser.parse_args()
-server = Server(expandpath(args.app) + '/',
-                expandpath(args.components) + '/',
-                args.plugins,
-                expandpath(args.plugin_root) + '/',
-                args.assets and expandpath(args.assets),
-                args.strip_assets,
-                expandpath(args.theme))
diff --git a/contrib/mitm-ui/serve-app-locally.py b/contrib/mitm-ui/serve-app-locally.py
deleted file mode 100644
index 636c68478e..0000000000
--- a/contrib/mitm-ui/serve-app-locally.py
+++ /dev/null
@@ -1,46 +0,0 @@
-# bazel build polygerrit-ui/app:gr-app
-# mitmdump -s "serve-app-locally.py ~/gerrit/bazel-bin/polygerrit-ui/app"
-from mitmproxy import http
-import argparse
-import os
-import zipfile
-
-class Server:
-    def __init__(self, bundle):
-        self.bundle = bundle
-        self.bundlemtime = 0
-        self.files = {
-            'polygerrit_ui/elements/gr-app.js': '',
-            'polygerrit_ui/elements/gr-app.html': '',
-            'polygerrit_ui/styles/main.css': '',
-        }
-        self.read_files()
-
-    def read_files(self):
-        if not os.path.isfile(self.bundle):
-            print("bundle not found!")
-            return
-        mtime = os.stat(self.bundle).st_mtime
-        if mtime <= self.bundlemtime:
-            return
-        self.bundlemtime = mtime
-        with zipfile.ZipFile(self.bundle) as z:
-            for fname in self.files:
-                print('Reading new content for ' + fname)
-                with z.open(fname, 'r') as content_file:
-                    self.files[fname] = content_file.read()
-
-    def response(self, flow: http.HTTPFlow) -> None:
-        self.read_files()
-        for name in self.files:
-            if name.rsplit('/', 1)[1] in flow.request.pretty_url:
-                flow.response.content = self.files[name]
-
-def expandpath(path):
-    return os.path.expanduser(path)
-
-def start():
-    parser = argparse.ArgumentParser()
-    parser.add_argument("bundle", type=str)
-    args = parser.parse_args()
-    return Server(expandpath(args.bundle))