It doesn't support WebExtensions (i.e. Chrome/Firefox extensions) unfortunately - see the FAQ in https://github.com/qutebrowser/qutebrowser/issues/30 for some details.

However, the new built-in adblocker does a big part of what uBlockOrigin does. As for uMatrix, there's https://gitlab.com/jgkamat/jmatrix (though it's a rather unofficial hack, and I have no idea if it still works with v2.0.0).

I'd really like to integrate something uMatrix-like (with nice keyboard usage) into qutebrowser some day, but so far I didn't get around to it: https://github.com/qutebrowser/qutebrowser/issues/28