This plugin checks the contrast as defined by WCAG2 and gives you a readability score for it.
You give it a foreground and background color in HEX and click the "> run test" button
You can load this plugin directly in Photoshop by using the UXP Developer Tools application. Once started, click "Add Plugin...", and navigate to the "manifest.json" file in this folder. Then click the ••• button next to the corresponding entry in the developer tools and click "Load". Switch over to Photoshop, and the plugin's panel will be running.
Inside the root directory