In reply to jeffc.
Comparing React and Vue’s licensing isn’t a direct comparison. React has a copyright license (BSD), and an additional patent grant. Vue only has a copyright license.

The effect of Facebook’s licensing is that you have a copy of the code under the BSD, and additionally, Facebook says “if we hold any patents that apply to this, you are free to use them”. This is a blanket patent license that Facebook applies to their open source projects, and doesn’t necessarily mean they do hold any relevant patents. If they do, you’re assured to be safe.

Vue’s license contains no such guarantees, as do most open source projects. If it turns out that Evan You (or his former employer, Google) do hold patents on the processes used by Vue, you have 0 protection from patent litigation.

This whole topic has been argued at length by armchair commentators, but Automattic has investigated this previously for Calypso licensing, and the outcome was that it didn’t matter.