Just tried to load the modified version of the Keep extension into my Opera GX. He states the extension is using outdated URLs (https://keep.google.com/keep instead of https://keep.google.com/) which results in a 404 error.

I downloaded his modded version and unpacked it. Switched on developer mode in the Extensions page, click "load unpacked" and point it to the "0.1.0_0" folder where manifest.json is at. That should install it.

Well, it doesn't work, just a quick spin of the progress wheel, nothing else. The unpacked manifest.json file can't be found by this in the selected folder. But it's quite obviously there when you open that folder with Windows 10 Explorer. Anybody know what's going on? Something is seriously broken. I tried this in Opera 77, same results, not working.