Greasy Fork is available in English.
サイトのすべてのRSSを表示します (あれば)
< RSS+ : 現在のサイトのRSSを表示についてのフィードバック
Which site can't work on? It's normal on my side.
It works. It shows a small dark gray circle on the bottom right corner of your browser. Make sure you don't have other possible icons in front of it, for example, like the AdGuard icon that is in the same place. In that case, this userscript icon would be hidden below it.
Not working, not even sure how this works!?