As a result of fwupd being blacklisted, it is now impossible to install kinfocenter. However, after a quick experiment, I found out that it is perfectly possible to build the package without having fwupd as a dependency, so I would suggest to move kinfocenter to libre and simply remove the dependency from the PKGBUILD. The only thing you'll notice when running kinfocenter is a screen that says ”The fwupdmgr tool is required to display this page, but could not be found.” (Screenshot attached.)