With this script, can you get the list of subcribers ?

I don’t think the Lemmy API exposes the subscriber list of a community, you’ll need access to the instance database.

What I did was checking every post for the last 365 days for user activity and store every user that have interacted with the community.

lemmy_session and lemmy_references are the same as for the LiveThreadBot (inside the src folder): https://gitlab.com/UlrikHD/lemmy-match-thread-bot

get_posts() may be missing from the lemmy_session.py file though

    def get_posts(self, *, community: int | str | LemmyCommunity, sort: str = 'New', page: int = 1) -> dict[str, any]:
        """ Gets the posts of a community.

        :param community: The ID of the community to get the posts of, can also be a LemmyCommunity parseable
        string/object.
        :param sort: The sorting method of the posts, by default 'New'.
        :param page: The page number of the posts, by default 1.
        :return: The response JSON of the request as a dictionary.
        """
        if isinstance(community, LemmyCommunity) or isinstance(community, str):
            response: Final[requests.Response] = self.srv.get_posts(community_name=community, sort=sort, page=page,
                                                                    limit=50)
        else:
            response: Final[requests.Response] = self.srv.get_posts(community_id=community, sort=sort, page=page,
                                                                    limit=50)
        if response.status_code != 200:
            raise requests.exceptions.HTTPError(response.text)
        return response.json()

Excuse the ugly code, it was written as a one-off

import os
import time
import datetime
from json import load, dump
import requests
from lemmy_references import LemmyCommunity, LemmyUser
from lemmy_session import LemmySession


session: LemmySession = LemmySession(website='https://lemmy.world/',
                                     username='TestUlrikHD',
                                     password='---',
                                     end_script_signal=None)

posts: list[dict[[str, any]]] = []
cutoff_date: datetime.datetime = datetime.datetime.now(datetime.timezone.utc) - datetime.timedelta(days=365)
page_count: int = 1
loop_break: bool = False
while True:
    post_response: dict[str, any] = session.get_posts(community=LemmyCommunity('football', 'lemmy.world'),
                                                      page=page_count)
    page_count += 1
    for post in post_response['posts']:
        if datetime.datetime.fromisoformat(post['post']['published']) > cutoff_date:
            posts.append(post)
        else:
            loop_break = True
            break
    if loop_break:
        break

user_dict: dict[str, dict[str, any]] = {}
for post in posts:
    user_dict[str(LemmyUser(post['creator']['actor_id']))] = {'post': True, 'post_id': post['post']['id']}
    comments = session.get_post_comments(post_id=post['post']['id'])
    for comment in comments['comments']:
        user: str = str(LemmyUser(comment['creator']['actor_id']))
        if user not in user_dict:
            user_dict[user] = {'post': False, 'post_id': comment['post']['id'], 'parent_id': comment['comment']['id']}
del user_dict[str(LemmyUser('FootballAutoMod@lemmy.world'))]
del user_dict[str(LemmyUser('LiveThreadBot@lemmy.world'))]
with open('user_dict', 'w', encoding='utf-8') as file:
    dump(user_dict, file, ensure_ascii=False, indent=4)


def log_reply(usr: str) -> None:
    user_list: list[str] = []
    if os.path.isfile('reply_list.json'):
        with open('reply_list.json', 'r', encoding='utf-8') as file:
            user_list = load(file)
    user_list.append(str(usr))
    with open('reply_list.json', 'w', encoding='utf-8') as file:
        dump(user_list, file, ensure_ascii=False, indent=4)


for username, user in user_dict.items():
    time.sleep(1)
    try:
        #if user['post']:
        #    session.reply(content='migration message', post_id=user['post_id'], parent_id=None)
        #else:
        #    session.reply(content='migration message', post_id=user['post_id'], parent_id=user['parent_id'])
        log_reply(usr=LemmyUser(username).str_link())
    except requests.HTTPError as e:
        print(f'Failed to send message to {username} - {e}')

and this part creates txt for easy copy pasting for tagging.

from json import load

with open('reply_list.json', 'r', encoding='utf-8') as file:
    user_list: list[str] = load(file)

loop_count: int = len(', '.join(user_list)) // 9500 + 1
for i in range(loop_count):
    with open(f'reply_list_{i}.txt', 'w', encoding='utf-8') as file:
        print(len(' '.join(user_list[i * len(user_list) // loop_count:(i + 1) * len(user_list) // loop_count])))
        file.write(', '.join(user_list[i * len(user_list) // loop_count:(i + 1) * len(user_list) // loop_count]))