For some time, quite a few ttf fonts have been distributed along with lyx in it's tarball. Now, an added wrinkle is http://wiki.lyx.org/FAQ/Qt which references what seems to be a slightly older separate copy of these same fonts.
Allow me to humbly request that these fonts (continue) to be distributed/released separately from lyx, and ensure that the aforementioned wiki docs are current. I don't mind if these continue to be included inside of lyx too, but I would like assurances that when/if the separate/embedded copies are in sync with each other. -- Rex