The Consent-O-Matic extension does not process any personal data. The only data that Consent-O-Matic stores (on your computer) are:
A count of pop-ups interacted with
A count of clicks saved
To delete all this data, simply uninstall the browser extension. To delete the counts of pop-ups and clicks without uninstalling, go to the About page in the extension settings and click the Clear button.
When you install Consent-O-Matic, you will see a pop-up from your browser that says it can "access your data for all websites" (or something similar depending on which browser you use). You get this warning because Consent-O-Matic needs access to the code of the website you're visiting to detect if there are any consent pop-ups and interact with them. We do not collect any data about the website you're visiting or what you do on the website: this warning is about what the extension has permission to do from the browser, not what it actually does.
The only time we will know which website you visit is when you report to us that the extension is not working on a particular page by clicking on the "Let us know!" button in the settings. In that case we receive a message on our server with the URL, which we store and look at to improve our coverage. The list of URLs might also be shared with other developers in the open-source community to further improve the extension. As part of how the web works, we will also receive your IP address when you send this URL, but we do not access or store this data. We process the IP on the basis of legitimate interest (i.e., we can't not receive it when you report a website).