This extension is very promising and I have worked with pleasure with the contrast function. 3 starred, because first feature "contrast" (and now newer features) are behind a login wall. There are other products (also extensions) out there that do some of these basic checks for "free", and have been doing this way longer than Stark is. Will re-use when at least contrast feature is provided without login. Thank you for your contribution to an Accessible web anyway!
The Stark Accessibility Checker plugin falls under the 'Accessibility Tools' category and offers subcategories such as Contrast Checker with Color Suggestions, Vision Simulator, Landmarks and Focus Order, Alt-Text Annotations, Typography Analysis, Touch Targets, and Live Preview
The plugin provides a suite of integrated accessibility tools for product design and development teams, aiming to increase velocity, accelerate compliance, and reduce costs in addressing accessibility issues