The meaning of this plugin? He does not work

Because the AMP page must have URL amp.example.com/page or example.com/amp/page

That’s not actually the case. Those are just examples. You can find the AMP version of a given URL on your site by looking at the amphtml link in the page. In Reader mode, currently only posts have AMP versions made available for them. So if you go to your most recently-published post, and look at the source code for the page, you should see that link. Otherwise, you can find the link to the AMP version in the admin bar.

Google does not perceive your pages as amp, even if you have a link to the amp page in your code, because the AMP page must have URL amp.example.com/page or example.com/amp/page
Show me a site with amp pages of your plugin in google index.

• This reply was modified 4 years, 9 months ago by Sergey.

Sure thing.

Here’s an example non-AMP page:

https://melchoyce.design/2020/03/30/creating-a-simple-block-pattern-plugin-for-the-gutenberg-editor/

This page contains a link to the AMP version:

<link rel="amphtml" href="https://melchoyce.design/2020/03/30/creating-a-simple-block-pattern-plugin-for-the-gutenberg-editor/amp/">

If I do a Google search for [creating a simple block pattern plugin for the gutenberg editor mel choyce] on mobile then I see the top result is for that linked AMP page: https://melchoyce.design/2020/03/30/creating-a-simple-block-pattern-plugin-for-the-gutenberg-editor/amp/

The search result has the AMP badge (lightning bolt).

I’m sorry, just now I see that google shows amp pages only for a key search query, and I can see that some pages of my site in google index with a symbol of lightning.
But a month ago, I could see amp pages on request from a computer site:example.com
Google also indexed my amp page as usual with link example.com/page/amp

• This reply was modified 4 years, 9 months ago by Sergey.
• This reply was modified 4 years, 9 months ago by Sergey.
• This reply was modified 4 years, 9 months ago by Sergey.