Put each plugin in its own folder under plugins/<name>/ with an __init__.py.
Keep plugin-specific assets beside the code in that same folder.
Single-file .py plugins are still supported, but package folders are the recommended plug-and-play format.

That means a plugin can ship as a drag-and-drop folder with extras such as:

cookies.txt
templates or fixture files
helper modules
small static assets

Built-in bundled plugins use the same layout as external plugins. Additional drop-in plugin search paths are:

plugins/ in the repo root
plugins/ in the current working directory
Any directory listed in MM_PLUGIN_PATH
Any directory listed in MEDEIA_PLUGIN_PATH

Plugin rules:

A plugin can be a single .py file or a package directory with __init__.py.
Define a class that inherits from ProviderCore.base.Provider.
Give it a stable name using PLUGIN_NAME or the class name.

Example skeleton:

from ProviderCore.base import Provider, SearchResult


class MyPlugin(Provider):
    PLUGIN_NAME = "myplugin"
    URL_DOMAINS = ("example.com",)

    def search(self, query, limit=50, filters=None, **kwargs):
        text = str(query or "").strip()
        if not text:
            return []
        return [
            SearchResult(
                table="myplugin",
                title=f"Result for {text}",
                path=f"https://example.com/{text}",
            )
        ]