diff --git a/doc/_extensions/lexer/DtsLexer.py b/doc/_extensions/lexer/DtsLexer.py
deleted file mode 100644
index 4fef4663c30..00000000000
--- a/doc/_extensions/lexer/DtsLexer.py
+++ /dev/null
@@ -1,90 +0,0 @@
-#!/usr/bin/python
-# SPDX-License-Identifier: BSD-2-Clause
-#
-# Contributors Listed Below - COPYRIGHT 2016
-# [+] International Business Machines Corp.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-# * Redistributions of source code must retain the above copyright
-#   notice, this list of conditions and the following disclaimer.
-#
-# * Redistributions in binary form must reproduce the above copyright
-#   notice, this list of conditions and the following disclaimer in the
-#  documentation and/or other materials provided with the distribution.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-from pygments.lexer import RegexLexer, bygroups, include
-from pygments.token import *
-
-__all__ = ['DtsLexer']
-
-class DtsLexer(RegexLexer):
-    name = 'DTS'
-    aliases = ['dts', 'device-tree']
-    filenames = ['*.dts']
-
-    tokens = {
-        'root': [
-            include('comments'),
-            (r'/memreserve/', Keyword, ('memreserve')),
-            (r'^/dts-v1/;$', Keyword),
-            (r'\s+', Text),
-            include('node'),
-        ],
-        'comments': [
-            (r'//(\n|(.|\n)*?[^\\]\n)', Comment.Single),
-            (r'/(\\\n)?[*](.|\n)*?[*](\\\n)?/', Comment.Multiline),
-        ],
-        'memreserve': [
-            include('comments'),
-            include('integers'),
-            (r'\s+', Text),
-            (r';', Punctuation, '#pop')
-        ],
-        'integers': [
-            (r'0x[0-9a-fA-F]+', Number.Hex),
-            (r'0[0-7]+', Number.Oct),
-            (r'\d+', Number.Integer),
-        ],
-        'node': [
-            (r'\s+', Text),
-            (r'((?:[0-9a-zA-Z,._+-]+):)?(\s*)([0-9a-zA-Z,._+-]+)(@[0-9a-zA-Z,._+-]+)?(\s*)({)', bygroups(Name.Label, Text, Name.Class, Name.Function, Text, Punctuation), ('node-content')),
-            (r'(/)(\s+)({)', bygroups(Keyword, Text, Punctuation), ('node-content')),
-        ],
-        'node-content': [
-            include('comments'),
-            include('node'),
-            (r'\s+', Text),
-            (r'([0-9a-zA-Z,._+-]+)(:)', bygroups(Name.Label, Punctuation)),
-            (r'([\#0-9a-zA-Z,._+-]+)(\s*)(=)(\s*)', bygroups(Name.Function, Text, Operator, Text), ('value')),
-            (r'([\#0-9a-zA-Z,._+-]+)(;)', bygroups(Name.Function, Punctuation)),
-            (r'};', Punctuation, ('#pop')),
-        ],
-        'value': [
-            include('integers'),
-            include('comments'),
-            (r'(\&)([a-zA-Z0-9_-]+)', bygroups(Operator, Text)),
-            (r'<', Punctuation, '#push'),
-            (r'>', Punctuation, '#pop'),
-            (r'\[', Punctuation, '#push'),
-            (r'\]', Punctuation, '#pop'),
-            (r'".*"', String),
-            (r';', Punctuation, '#pop'),
-            (r'\s+', Text),
-            (r',', Punctuation)
-        ],
-    }
diff --git a/doc/_extensions/lexer/__init__.py b/doc/_extensions/lexer/__init__.py
deleted file mode 100644
index c62af8e8f4d..00000000000
--- a/doc/_extensions/lexer/__init__.py
+++ /dev/null
@@ -1,4 +0,0 @@
-# Copyright (c) 2021 Zephyr Project members and individual contributors
-# SPDX-License-Identifier: Apache-2.0
-
-# File intentionally empty