Very nice little add-on. Would love a keyboard shortcut.

This is a breakthrough.
It has the effect of applying a Photoshop like filter to your web screen.
It will be easier to see if you use it on a difficult-to-see website created by an individual or an amateur. Also effective for images and videos.
Issues.
(1) No grayscale conversion based on "luminance" has been done. It is not "brightness".
(2) Invalid for some background colors and scroll bar colors.
(3) Menus and small window videos disappear. The page layout changes a little.

これは非常に画期的です。
ウェブ画面にPhotoshopフィルタを適用させたような効果が得られます。
これを個人や素人が作った見にくいウェブサイトに使うと見やすくなるでしょう。画像や動画にも有効。
問題点。
①「輝度」を基準にグレースケール変換されていない。「明度」じゃありあせん。
②一部の背景色やスクロールバー色に対して無効。
③メニューや小窓動画が消える。ページレイアウトが少し変わる。

https://color.adobe.com/create/color-wheel
https://www.tomojuku.com/blog/
https://www.youtube.com/results?search_query=easy+to+see

Works great for checking my products for colorblindness. Also, YouTube works fine for me with the extension on.

Completely breaks YouTube.

Needs a shortcut, great otherwise

It's great and functional . Adding an option to toggle either per site or per tab and for me it would be perfect

Love the idea, thanks! Doesn't work on all tabs, e.g. the one in which I'm writing this review...actually no tabs in addons.mozilla.org seem to work. But more importantly it needs a toggle hotkey, I can't use it without that.

Really functional to make (social media) websites more boring and thus less addictive. I would give 5 stars if I could turn it on/off per website!