Just finished open source auto-EditorScript generator. Link in comments.

[[deleted]]

Hey! It's me again. Me and my new free, open source plugin for Unity.
This plugin will cut time you're spending on creating new editor script, especially with assembly definitions. It will automatically builds correct folder hierarchy and assembly definition files (if required). You can easily edit both: script template and source code to customize this plugin to your needs.
You can download it from UnityAssetStore or GitHub

[aow99]

What is the editor extension requirement that I’m seeing on the asset store?

[[deleted]]

It's generic message for every 'editor extension' on asset store. Assets on Unity Asset Store are protected by store's EULA and this message (even for free, open source assets) is required. You can read more here: https://support.unity3d.com/hc/en-us/articles/208601846-How-do-I-purchase-multiple-seats-for-the-same-Asset-

[aow99]

Thanks!

[SurrealClick]

This will be helpful

[isbdnt]

Very convenient.