Cookies not being automatically cleared upon exit of tab or browser
Verification that cookies have not been deleted:
In Kiwi Browser's Clear Data section (cookies still there.

No deleted cookies in CAD's logs.

鈥nstall Kiwi Browser from Play Store
鈥nstall CAD on Kiwi Browser for Android via the chrome extension store
鈥nable automatic cleanups, etc.
鈥lose tabs and/or browser
鈥tart browser back up and check to see if cookies were deleted

I was going to open the same issue today!
I confirm the same problem.
Having it fixed would be just great
Chrome support is only valid on Desktops. Native Chrome browsers on Android don't have webextension support (at least not for this webextension nor any with 'cookie' keyword on it) so I don't think we can do much here.
Check with the author of that browser app to see if they have successfully implemented the chrome.cookies API (https://developer.chrome.com/extensions/cookies).
At this point, the 'Available for Android' option in the Chrome Web Store links that web app/extension to its Play Store version, which is technically a separate app altogether.
yup...
https://github.com/kiwibrowser/android/blob/master/chrome/common/extensions/api/cookies.json
EDIT:
All my other extensions all work properly, too.
Hmmm...It's not that [the author] doesn't want to support it, but much like Opera and Waterfox, support isn't guaranteed for those either.
Also that page may have been simply forked over from the chromium project - not sure how he actually packaged it all into an APK and made it work.
See if the XDA community have any details on making it work, as some may have gotten it work. If you can troubleshoot and figure out where that bug is on that browser, then by all means leave a detailed bug screenshot showing where the error is.
Closing this issue due to unofficially supported browser.
Most helpful comment
I was going to open the same issue today!
I confirm the same problem.
Having it fixed would be just great