Manifest version 2 is deprecated
the extension will stop working in the future:
Manifest version 2 is deprecated, and support will be removed in 2023. See https://developer.chrome.com/blog/mv2-transition/ for more details.
on Chromium 101.0.4951.41
After updating to the latest Chromium version, I ended up with the following warning:
This extension may soon no longer be supported because it doesn't follow best practices for Chrome extensions.
Apparently this is now shown when extensions are not using Manifest V3.
I've had a couple of goes at converting to Manifest v3 but I ended up breaking things. Unless someone with more Javascript skill is willing to take this on the extension will just become Firefox only and stick to Manifest v2. I've stopped using Chrome for everything apart from the occasional corporate thing and therefor I never really use the extension on anything other than Firefox.