contrib: remove copyright_header.py

diff --git a/contrib/devtools/README.md b/contrib/devtools/README.md
index 3309057b..50e80781 100644
--- a/contrib/devtools/README.md
+++ b/contrib/devtools/README.md
@@ -61,65 +61,6 @@ the script should be called from the git root folder as follows.
 git diff -U0 HEAD~1.. | ./contrib/devtools/clang-format-diff.py -p1 -i -v
 ```
 
-copyright\_header.py
-====================
-
-Provides utilities for managing copyright headers of `The Bitcoin Core
-developers` in repository source files. It has three subcommands:
-
-```
-$ ./copyright_header.py report <base_directory> [verbose]
-$ ./copyright_header.py update <base_directory>
-$ ./copyright_header.py insert <file>
-```
-Running these subcommands without arguments displays a usage string.
-
-copyright\_header.py report \<base\_directory\> [verbose]
----------------------------------------------------------
-
-Produces a report of all copyright header notices found inside the source files
-of a repository. Useful to quickly visualize the state of the headers.
-Specifying `verbose` will list the full filenames of files of each category.
-
-copyright\_header.py update \<base\_directory\> [verbose]
----------------------------------------------------------
-Updates all the copyright headers of `The Bitcoin Core developers` which were
-changed in a year more recent than is listed. For example:
-```
-// Copyright (c) <firstYear>-<lastYear> The Bitcoin Core developers
-```
-will be updated to:
-```
-// Copyright (c) <firstYear>-<lastModifiedYear> The Bitcoin Core developers
-```
-where `<lastModifiedYear>` is obtained from the `git log` history.
-
-This subcommand also handles copyright headers that have only a single year. In
-those cases:
-```
-// Copyright (c) <year> The Bitcoin Core developers
-```
-will be updated to:
-```
-// Copyright (c) <year>-<lastModifiedYear> The Bitcoin Core developers
-```
-where the update is appropriate.
-
-copyright\_header.py insert \<file\>
-------------------------------------
-Inserts a copyright header for `The Bitcoin Core developers` at the top of the
-file in either Python or C++ style as determined by the file extension. If the
-file is a Python file and it has  `#!` starting the first line, the header is
-inserted in the line below it.
-
-The copyright dates will be set to be `<year_introduced>-<current_year>` where
-`<year_introduced>` is according to the `git log` history. If
-`<year_introduced>` is equal to `<current_year>`, it will be set as a single
-year rather than two hyphenated years.
-
-If the file already has a copyright for `The Bitcoin Core developers`, the
-script will exit.
-
 gen-manpages.py
 ===============
 
diff --git a/contrib/devtools/copyright_header.py b/contrib/devtools/copyright_header.py
deleted file mode 100755
index aa77de8a..00000000
--- a/contrib/devtools/copyright_header.py
+++ /dev/null
@@ -1,601 +0,0 @@
-#!/usr/bin/env python3
-# Copyright (c) 2016-present The Bitcoin Core developers
-# Distributed under the MIT software license, see the accompanying
-# file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-import re
-import fnmatch
-import sys
-import subprocess
-import datetime
-import os
-
-################################################################################
-# file filtering
-################################################################################
-
-EXCLUDE = [
-    # auto generated:
-    'src/qt/bitcoinstrings.cpp',
-    'src/chainparamsseeds.h',
-    # other external copyrights:
-    'src/test/fuzz/FuzzedDataProvider.h',
-    'src/tinyformat.h',
-    'src/bench/nanobench.h',
-    # python init:
-    '*__init__.py',
-]
-EXCLUDE_COMPILED = re.compile('|'.join([fnmatch.translate(m) for m in EXCLUDE]))
-
-EXCLUDE_DIRS = [
-    # git subtrees
-    "src/crypto/ctaes/",
-    "src/leveldb/",
-    "src/minisketch",
-    "src/secp256k1/",
-    "src/crc32c/",
-]
-
-INCLUDE = ['*.h', '*.cpp', '*.cc', '*.c', '*.mm', '*.py', '*.sh', '*.bash-completion']
-INCLUDE_COMPILED = re.compile('|'.join([fnmatch.translate(m) for m in INCLUDE]))
-
-def applies_to_file(filename):
-    for excluded_dir in EXCLUDE_DIRS:
-        if filename.startswith(excluded_dir):
-            return False
-    return ((EXCLUDE_COMPILED.match(filename) is None) and
-            (INCLUDE_COMPILED.match(filename) is not None))
-
-################################################################################
-# obtain list of files in repo according to INCLUDE and EXCLUDE
-################################################################################
-
-GIT_LS_CMD = 'git ls-files --full-name'.split(' ')
-GIT_TOPLEVEL_CMD = 'git rev-parse --show-toplevel'.split(' ')
-
-def call_git_ls(base_directory):
-    out = subprocess.check_output([*GIT_LS_CMD, base_directory], text=True)
-    return [f for f in out.split('\n') if f != '']
-
-def call_git_toplevel():
-    "Returns the absolute path to the project root"
-    return subprocess.check_output(GIT_TOPLEVEL_CMD, text=True).strip()
-
-def get_filenames_to_examine(base_directory):
-    "Returns an array of absolute paths to any project files in the base_directory that pass the include/exclude filters"
-    root = call_git_toplevel()
-    filenames = call_git_ls(base_directory)
-    return sorted([os.path.join(root, filename) for filename in filenames if
-                   applies_to_file(filename)])
-
-################################################################################
-# define and compile regexes for the patterns we are looking for
-################################################################################
-
-
-COPYRIGHT_WITH_C = r'Copyright \(c\)'
-COPYRIGHT_WITHOUT_C = 'Copyright'
-ANY_COPYRIGHT_STYLE = '(%s|%s)' % (COPYRIGHT_WITH_C, COPYRIGHT_WITHOUT_C)
-
-YEAR = "20[0-9][0-9]"
-YEAR_RANGE = '(%s)(-%s)?' % (YEAR, YEAR)
-YEAR_LIST = '(%s)(, %s)+' % (YEAR, YEAR)
-ANY_YEAR_STYLE = '(%s|%s)' % (YEAR_RANGE, YEAR_LIST)
-ANY_COPYRIGHT_STYLE_OR_YEAR_STYLE = ("%s %s" % (ANY_COPYRIGHT_STYLE,
-                                                ANY_YEAR_STYLE))
-
-ANY_COPYRIGHT_COMPILED = re.compile(ANY_COPYRIGHT_STYLE_OR_YEAR_STYLE)
-
-def compile_copyright_regex(copyright_style, year_style, name):
-    return re.compile(r'%s %s,? %s( +\*)?\n' % (copyright_style, year_style, name))
-
-EXPECTED_HOLDER_NAMES = [
-    r"Satoshi Nakamoto",
-    r"The Bitcoin Core developers",
-    r"BitPay Inc\.",
-    r"Pieter Wuille",
-    r"Wladimir J\. van der Laan",
-    r"Jeff Garzik",
-    r"Jan-Klaas Kollhof",
-    r"ArtForz -- public domain half-a-node",
-    r"Intel Corporation ?",
-    r"The Zcash developers",
-    r"Jeremy Rubin",
-]
-
-DOMINANT_STYLE_COMPILED = {}
-YEAR_LIST_STYLE_COMPILED = {}
-WITHOUT_C_STYLE_COMPILED = {}
-
-for holder_name in EXPECTED_HOLDER_NAMES:
-    DOMINANT_STYLE_COMPILED[holder_name] = (
-        compile_copyright_regex(COPYRIGHT_WITH_C, YEAR_RANGE, holder_name))
-    YEAR_LIST_STYLE_COMPILED[holder_name] = (
-        compile_copyright_regex(COPYRIGHT_WITH_C, YEAR_LIST, holder_name))
-    WITHOUT_C_STYLE_COMPILED[holder_name] = (
-        compile_copyright_regex(COPYRIGHT_WITHOUT_C, ANY_YEAR_STYLE,
-                                holder_name))
-
-################################################################################
-# search file contents for copyright message of particular category
-################################################################################
-
-def get_count_of_copyrights_of_any_style_any_holder(contents):
-    return len(ANY_COPYRIGHT_COMPILED.findall(contents))
-
-def file_has_dominant_style_copyright_for_holder(contents, holder_name):
-    match = DOMINANT_STYLE_COMPILED[holder_name].search(contents)
-    return match is not None
-
-def file_has_year_list_style_copyright_for_holder(contents, holder_name):
-    match = YEAR_LIST_STYLE_COMPILED[holder_name].search(contents)
-    return match is not None
-
-def file_has_without_c_style_copyright_for_holder(contents, holder_name):
-    match = WITHOUT_C_STYLE_COMPILED[holder_name].search(contents)
-    return match is not None
-
-################################################################################
-# get file info
-################################################################################
-
-def read_file(filename):
-    return open(filename, 'r').read()
-
-def gather_file_info(filename):
-    info = {}
-    info['filename'] = filename
-    c = read_file(filename)
-    info['contents'] = c
-
-    info['all_copyrights'] = get_count_of_copyrights_of_any_style_any_holder(c)
-
-    info['classified_copyrights'] = 0
-    info['dominant_style'] = {}
-    info['year_list_style'] = {}
-    info['without_c_style'] = {}
-    for holder_name in EXPECTED_HOLDER_NAMES:
-        has_dominant_style = (
-            file_has_dominant_style_copyright_for_holder(c, holder_name))
-        has_year_list_style = (
-            file_has_year_list_style_copyright_for_holder(c, holder_name))
-        has_without_c_style = (
-            file_has_without_c_style_copyright_for_holder(c, holder_name))
-        info['dominant_style'][holder_name] = has_dominant_style
-        info['year_list_style'][holder_name] = has_year_list_style
-        info['without_c_style'][holder_name] = has_without_c_style
-        if has_dominant_style or has_year_list_style or has_without_c_style:
-            info['classified_copyrights'] = info['classified_copyrights'] + 1
-    return info
-
-################################################################################
-# report execution
-################################################################################
-
-SEPARATOR = '-'.join(['' for _ in range(80)])
-
-def print_filenames(filenames, verbose):
-    if not verbose:
-        return
-    for filename in filenames:
-        print("\t%s" % filename)
-
-def print_report(file_infos, verbose):
-    print(SEPARATOR)
-    examined = [i['filename'] for i in file_infos]
-    print("%d files examined according to INCLUDE and EXCLUDE fnmatch rules" %
-          len(examined))
-    print_filenames(examined, verbose)
-
-    print(SEPARATOR)
-    print('')
-    zero_copyrights = [i['filename'] for i in file_infos if
-                       i['all_copyrights'] == 0]
-    print("%4d with zero copyrights" % len(zero_copyrights))
-    print_filenames(zero_copyrights, verbose)
-    one_copyright = [i['filename'] for i in file_infos if
-                     i['all_copyrights'] == 1]
-    print("%4d with one copyright" % len(one_copyright))
-    print_filenames(one_copyright, verbose)
-    two_copyrights = [i['filename'] for i in file_infos if
-                      i['all_copyrights'] == 2]
-    print("%4d with two copyrights" % len(two_copyrights))
-    print_filenames(two_copyrights, verbose)
-    three_copyrights = [i['filename'] for i in file_infos if
-                        i['all_copyrights'] == 3]
-    print("%4d with three copyrights" % len(three_copyrights))
-    print_filenames(three_copyrights, verbose)
-    four_or_more_copyrights = [i['filename'] for i in file_infos if
-                               i['all_copyrights'] >= 4]
-    print("%4d with four or more copyrights" % len(four_or_more_copyrights))
-    print_filenames(four_or_more_copyrights, verbose)
-    print('')
-    print(SEPARATOR)
-    print('Copyrights with dominant style:\ne.g. "Copyright (c)" and '
-          '"<year>" or "<startYear>-<endYear>":\n')
-    for holder_name in EXPECTED_HOLDER_NAMES:
-        dominant_style = [i['filename'] for i in file_infos if
-                          i['dominant_style'][holder_name]]
-        if len(dominant_style) > 0:
-            print("%4d with '%s'" % (len(dominant_style),
-                                     holder_name.replace('\n', '\\n')))
-            print_filenames(dominant_style, verbose)
-    print('')
-    print(SEPARATOR)
-    print('Copyrights with year list style:\ne.g. "Copyright (c)" and '
-          '"<year1>, <year2>, ...":\n')
-    for holder_name in EXPECTED_HOLDER_NAMES:
-        year_list_style = [i['filename'] for i in file_infos if
-                           i['year_list_style'][holder_name]]
-        if len(year_list_style) > 0:
-            print("%4d with '%s'" % (len(year_list_style),
-                                     holder_name.replace('\n', '\\n')))
-            print_filenames(year_list_style, verbose)
-    print('')
-    print(SEPARATOR)
-    print('Copyrights with no "(c)" style:\ne.g. "Copyright" and "<year>" or '
-          '"<startYear>-<endYear>":\n')
-    for holder_name in EXPECTED_HOLDER_NAMES:
-        without_c_style = [i['filename'] for i in file_infos if
-                           i['without_c_style'][holder_name]]
-        if len(without_c_style) > 0:
-            print("%4d with '%s'" % (len(without_c_style),
-                                     holder_name.replace('\n', '\\n')))
-            print_filenames(without_c_style, verbose)
-
-    print('')
-    print(SEPARATOR)
-
-    unclassified_copyrights = [i['filename'] for i in file_infos if
-                               i['classified_copyrights'] < i['all_copyrights']]
-    print("%d with unexpected copyright holder names" %
-          len(unclassified_copyrights))
-    print_filenames(unclassified_copyrights, verbose)
-    print(SEPARATOR)
-
-def exec_report(base_directory, verbose):
-    filenames = get_filenames_to_examine(base_directory)
-    file_infos = [gather_file_info(f) for f in filenames]
-    print_report(file_infos, verbose)
-
-################################################################################
-# report cmd
-################################################################################
-
-REPORT_USAGE = """
-Produces a report of all copyright header notices found inside the source files
-of a repository.
-
-Usage:
-    $ ./copyright_header.py report <base_directory> [verbose]
-
-Arguments:
-    <base_directory> - The base directory of a bitcoin source code repository.
-    [verbose] - Includes a list of every file of each subcategory in the report.
-"""
-
-def report_cmd(argv):
-    if len(argv) == 2:
-        sys.exit(REPORT_USAGE)
-
-    base_directory = argv[2]
-    if not os.path.exists(base_directory):
-        sys.exit("*** bad <base_directory>: %s" % base_directory)
-
-    if len(argv) == 3:
-        verbose = False
-    elif argv[3] == 'verbose':
-        verbose = True
-    else:
-        sys.exit("*** unknown argument: %s" % argv[2])
-
-    exec_report(base_directory, verbose)
-
-################################################################################
-# query git for year of last change
-################################################################################
-
-GIT_LOG_CMD = "git log --pretty=format:%%ai %s"
-
-def call_git_log(filename):
-    out = subprocess.check_output((GIT_LOG_CMD % filename).split(' '), text=True)
-    return out.split('\n')
-
-def get_git_change_years(filename):
-    git_log_lines = call_git_log(filename)
-    if len(git_log_lines) == 0:
-        return [datetime.date.today().year]
-    # timestamp is in ISO 8601 format. e.g. "2016-09-05 14:25:32 -0600"
-    return [line.split(' ')[0].split('-')[0] for line in git_log_lines]
-
-def get_most_recent_git_change_year(filename):
-    return max(get_git_change_years(filename))
-
-################################################################################
-# read and write to file
-################################################################################
-
-def read_file_lines(filename):
-    with open(filename, 'r') as f:
-        file_lines = f.readlines()
-    return file_lines
-
-def write_file_lines(filename, file_lines):
-    with open(filename, 'w') as f:
-        f.write(''.join(file_lines))
-
-################################################################################
-# update header years execution
-################################################################################
-
-COPYRIGHT = r'Copyright \(c\)'
-YEAR = "20[0-9][0-9]"
-YEAR_RANGE = '(%s)(-%s)?' % (YEAR, YEAR)
-HOLDER = 'The Bitcoin Core developers'
-UPDATEABLE_LINE_COMPILED = re.compile(' '.join([COPYRIGHT, YEAR_RANGE, HOLDER]))
-
-def get_updatable_copyright_line(file_lines):
-    index = 0
-    for line in file_lines:
-        if UPDATEABLE_LINE_COMPILED.search(line) is not None:
-            return index, line
-        index = index + 1
-    return None, None
-
-def parse_year_range(year_range):
-    year_split = year_range.split('-')
-    start_year = year_split[0]
-    if len(year_split) == 1:
-        return start_year, start_year
-    return start_year, year_split[1]
-
-def year_range_to_str(start_year, end_year):
-    if start_year == end_year:
-        return start_year
-    return "%s-%s" % (start_year, end_year)
-
-def create_updated_copyright_line(line, last_git_change_year):
-    copyright_splitter = 'Copyright (c) '
-    copyright_split = line.split(copyright_splitter)
-    # Preserve characters on line that are ahead of the start of the copyright
-    # notice - they are part of the comment block and vary from file-to-file.
-    before_copyright = copyright_split[0]
-    after_copyright = copyright_split[1]
-
-    space_split = after_copyright.split(' ')
-    year_range = space_split[0]
-    start_year, end_year = parse_year_range(year_range)
-    if end_year >= last_git_change_year:
-        return line
-    return (before_copyright + copyright_splitter +
-            year_range_to_str(start_year, last_git_change_year) + ' ' +
-            ' '.join(space_split[1:]))
-
-def update_updatable_copyright(filename):
-    file_lines = read_file_lines(filename)
-    index, line = get_updatable_copyright_line(file_lines)
-    if not line:
-        print_file_action_message(filename, "No updatable copyright.")
-        return
-    last_git_change_year = get_most_recent_git_change_year(filename)
-    new_line = create_updated_copyright_line(line, last_git_change_year)
-    if line == new_line:
-        print_file_action_message(filename, "Copyright up-to-date.")
-        return
-    file_lines[index] = new_line
-    write_file_lines(filename, file_lines)
-    print_file_action_message(filename,
-                              "Copyright updated! -> %s" % last_git_change_year)
-
-def exec_update_header_year(base_directory):
-    for filename in get_filenames_to_examine(base_directory):
-        update_updatable_copyright(filename)
-
-################################################################################
-# update cmd
-################################################################################
-
-UPDATE_USAGE = """
-Updates all the copyright headers of "The Bitcoin Core developers" which were
-changed in a year more recent than is listed. For example:
-
-// Copyright (c) <firstYear>-<lastYear> The Bitcoin Core developers
-
-will be updated to:
-
-// Copyright (c) <firstYear>-<lastModifiedYear> The Bitcoin Core developers
-
-where <lastModifiedYear> is obtained from the 'git log' history.
-
-This subcommand also handles copyright headers that have only a single year. In those cases:
-
-// Copyright (c) <year> The Bitcoin Core developers
-
-will be updated to:
-
-// Copyright (c) <year>-<lastModifiedYear> The Bitcoin Core developers
-
-where the update is appropriate.
-
-Usage:
-    $ ./copyright_header.py update <base_directory>
-
-Arguments:
-    <base_directory> - The base directory of a bitcoin source code repository.
-"""
-
-def print_file_action_message(filename, action):
-    print("%-52s %s" % (filename, action))
-
-def update_cmd(argv):
-    if len(argv) != 3:
-        sys.exit(UPDATE_USAGE)
-
-    base_directory = argv[2]
-    if not os.path.exists(base_directory):
-        sys.exit("*** bad base_directory: %s" % base_directory)
-    exec_update_header_year(base_directory)
-
-################################################################################
-# inserted copyright header format
-################################################################################
-
-def get_header_lines(header, start_year, end_year):
-    lines = header.split('\n')[1:-1]
-    lines[0] = lines[0] % year_range_to_str(start_year, end_year)
-    return [line + '\n' for line in lines]
-
-CPP_HEADER = '''
-// Copyright (c) %s The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-'''
-
-def get_cpp_header_lines_to_insert(start_year, end_year):
-    return reversed(get_header_lines(CPP_HEADER, start_year, end_year))
-
-SCRIPT_HEADER = '''
-# Copyright (c) %s The Bitcoin Core developers
-# Distributed under the MIT software license, see the accompanying
-# file COPYING or http://www.opensource.org/licenses/mit-license.php.
-'''
-
-def get_script_header_lines_to_insert(start_year, end_year):
-    return reversed(get_header_lines(SCRIPT_HEADER, start_year, end_year))
-
-################################################################################
-# query git for year of last change
-################################################################################
-
-def get_git_change_year_range(filename):
-    years = get_git_change_years(filename)
-    return min(years), max(years)
-
-################################################################################
-# check for existing core copyright
-################################################################################
-
-def file_already_has_core_copyright(file_lines):
-    index, _ = get_updatable_copyright_line(file_lines)
-    return index is not None
-
-################################################################################
-# insert header execution
-################################################################################
-
-def file_has_hashbang(file_lines):
-    if len(file_lines) < 1:
-        return False
-    if len(file_lines[0]) <= 2:
-        return False
-    return file_lines[0][:2] == '#!'
-
-def insert_script_header(filename, file_lines, start_year, end_year):
-    if file_has_hashbang(file_lines):
-        insert_idx = 1
-    else:
-        insert_idx = 0
-    header_lines = get_script_header_lines_to_insert(start_year, end_year)
-    for line in header_lines:
-        file_lines.insert(insert_idx, line)
-    write_file_lines(filename, file_lines)
-
-def insert_cpp_header(filename, file_lines, start_year, end_year):
-    file_lines.insert(0, '\n')
-    header_lines = get_cpp_header_lines_to_insert(start_year, end_year)
-    for line in header_lines:
-        file_lines.insert(0, line)
-    write_file_lines(filename, file_lines)
-
-def exec_insert_header(filename, style):
-    file_lines = read_file_lines(filename)
-    if file_already_has_core_copyright(file_lines):
-        sys.exit('*** %s already has a copyright by The Bitcoin Core developers'
-                 % (filename))
-    start_year, end_year = get_git_change_year_range(filename)
-    if style in ['python', 'shell']:
-        insert_script_header(filename, file_lines, start_year, end_year)
-    else:
-        insert_cpp_header(filename, file_lines, start_year, end_year)
-
-################################################################################
-# insert cmd
-################################################################################
-
-INSERT_USAGE = """
-Inserts a copyright header for "The Bitcoin Core developers" at the top of the
-file in either Python or C++ style as determined by the file extension. If the
-file is a Python file and it has a '#!' starting the first line, the header is
-inserted in the line below it.
-
-The copyright dates will be set to be:
-
-"<year_introduced>-<current_year>"
-
-where <year_introduced> is according to the 'git log' history. If
-<year_introduced> is equal to <current_year>, the date will be set to be:
-
-"<current_year>"
-
-If the file already has a copyright for "The Bitcoin Core developers", the
-script will exit.
-
-Usage:
-    $ ./copyright_header.py insert <file>
-
-Arguments:
-    <file> - A source file in the bitcoin repository.
-"""
-
-def insert_cmd(argv):
-    if len(argv) != 3:
-        sys.exit(INSERT_USAGE)
-
-    filename = argv[2]
-    if not os.path.isfile(filename):
-        sys.exit("*** bad filename: %s" % filename)
-    _, extension = os.path.splitext(filename)
-    if extension not in ['.h', '.cpp', '.cc', '.c', '.py', '.sh']:
-        sys.exit("*** cannot insert for file extension %s" % extension)
-
-    if extension == '.py':
-        style = 'python'
-    elif extension == '.sh':
-        style = 'shell'
-    else:
-        style = 'cpp'
-    exec_insert_header(filename, style)
-
-################################################################################
-# UI
-################################################################################
-
-USAGE = """
-copyright_header.py - utilities for managing copyright headers of 'The Bitcoin
-Core developers' in repository source files.
-
-Usage:
-    $ ./copyright_header <subcommand>
-
-Subcommands:
-    report
-    update
-    insert
-
-To see subcommand usage, run them without arguments.
-"""
-
-SUBCOMMANDS = ['report', 'update', 'insert']
-
-if __name__ == "__main__":
-    if len(sys.argv) == 1:
-        sys.exit(USAGE)
-    subcommand = sys.argv[1]
-    if subcommand not in SUBCOMMANDS:
-        sys.exit(USAGE)
-    if subcommand == 'report':
-        report_cmd(sys.argv)
-    elif subcommand == 'update':
-        update_cmd(sys.argv)
-    elif subcommand == 'insert':
-        insert_cmd(sys.argv)