> The advantage of installing Symbola is twofold: (1) Emacs knows about > Symbola and will automatically use it if available; (2) it is a free > font, unlike some of those mentioned by that URL. (And Symbola > supports a lot of other characters, so installing it is a net win.)
Symbola seems to be licensed only for personal use as of version 11 (June 2018), I think. See the License link on http://users.teilar.gr/~g1951d/ -- Cecilio Pardo