They don't specify, but it seems frequent enough in my experience. Here is what the Web site says: "LibreWolf is always built from the latest Firefox stable source, for up-to-date security and features along with stability."
> How does it fight against the duopoly of Google and Apple on the web? It uses Gecko rather than Blink or WebKit if that's what your question is asking. It's just standard Firefox with privacy tweaks and patches applied out of the box.