In this post I use the term native browser plugin for lack of a better term in my vocabulary.

Today I was talking to someone about Unity, a popular game engine. I'm not into games but I remember Unity had a 'web player' plugin for the browser, probably extending the browser to do things it can not do by itself.

I was asked if nowadays there is any recommended standard when it comes to creating plugins like that. Perhaps something consistently implemented by multiple browsers. I had no answer but figured there probably is such a thing so went to go look for one.

When I Googled this Unity web player I discovered that things have changed.

The Unity Webplayer is no longer supported. We provide this download link to the last build for convenience, but be aware that the Unity Webplayer has been deprecated and will not get any further update.
If you want to deliver Unity made content via web browser we recommend you use Unity WebGL.

Do we still create 'native' plugins for the browser or is this considered universally deprecated? Are there any standards? What do you call these type of plugins and where do I find more information? If 'native' plugins are indeed not the way to go, does that mean we are limited to using only functionality supported by browser extensions?

I am very curious about this and am looking forward to reading your answers.