Let visitors find out how site is customized?

When I visit certain sites, I think to myself: is this WP? what theme is this? how has the theme been customized? what plugins are being used?

Ideally, I would be able to view the Additional CSS for the site, and a list of the active plugins. I don’t think that this is possible by default. But could the site owner make it possible, if they wanted to share or show off their work?

To come at the same question from the other side… I’ve moved my site from wp.com to siteground. I’m using Twenty Sixteen (I know, literally so last year, but I like that clean old-school blog look). I have some additional CSS.

I was going to write a post about the customization, including a paste-in of the additional CSS. But what happens if and when I add to the additional CSS? I don’t want to have to update the post. But I don’t want the post to go stale by not reflecting the latest and greatest CSS.

I can’t find a “show customizations” plugin. It would allow me to select aspects of site customization that interested visitors could see. I’d check boxes such as
“Additional CSS” and “Plugins list”.

Is there such a plugin? If not, are there other ways of achieving what I want?

Thanks very much,
Andrew

ps This is my first post to these forums in seven years? I was at wp.com for a lot longer than I thought I would be!

pps The site is changingway.org

ppps Sorry if you are a security specialist terrified by the above. I wish you a full and speedy recovery from the heart attack. If there is no safe way to do this, please let me know, and I just won’t do it.