Adding metadata provider as plugin

[ndonkersloot]

In my local Calibre I use the BOL_NL plugin to fetch metadata from the dutch book store 'BOL', this works well.

I want to use this plugin in CWA but I cannot get it to work, should it work?
This is my docker-compose.yml

services:
  calibre-web-automated:
    image: crocodilestick/calibre-web-automated:latest
    container_name: tool-calibre-web-automated
    environment:
      - PUID=1043
      - PGID=65539
      - TZ=Europe/Amsterdam
      - UMASK_SET=022
    volumes:
      - ./import:/cwa-book-ingest
      - ./config/calibre-web:/config
      - ./config/calibre-library:/calibre-library
      - ./config/plugins:/config/.config/calibre/plugins
    ports:
      - 8087:8083
    restart: unless-stopped

I've placed the BOL_NL.zip file in the ./config/plugins folder, I can see that it is available inside the container.
I've copied my customize.py.json and placed it in the ./config/calibre-web folder with these contents:

{
  "disabled_plugins": {
    "__class__": "set",
    "__value__": [
      "Open Library"
    ]
  },
  "enabled_plugins": {
    "__class__": "set",
    "__value__": [
      "BOL_NL",
      "Amazon.com",
      "Google"
    ]
  },
  "filetype_mapping": {},
  "plugin_customization": {},
  "plugins": {
    "BOL_NL": "/config/.config/calibre/plugins/BOL_NL.zip"
  }
}

In my local Calibre I now have BOL_NL as a metadata fetcher available, but in CWA this doesn't work.
I'm not sure if it is supposed to work like this?