I read this: https://duo.com/decipher/malicious-chrome-extension-backdoor-uncovered-in-malware-campaign#:~:text=One%20of%20these%20is%20a,system%20and%20installing%20the%20extension. I quote this part from that article:
The browser extension, which includes samples dating back to August 2018, is delivered via an executable (not from the Chrome Extension store) with the sole function of preparing the system and installing the extension.
You can install a Chrome extension with the registry in Windows, but then the extension has to be on the Chrome Extension Store. How is it possible that a .exe file can install a chrome extension without the extension being published online?