With ColorZilla you can get a color reading from any point in your browser, quickly adjust this color and paste it into another program.
This resource is not recommended because:
Resource has not been updated since 2016.
Vulnerability identified that opens the possibility to allow for cross-site scripting and the injection of malicious code.
Because this resource requires permissions to "Read and change all your data on the websites you visit" the possibility of malicious code injection is a threat.