A right to a free, quality public education
Let's look at what this means.
'a right' -- in order for something to be a right, it must be inalienable. That is, it cannot be take away from you as it is inherent. And a right does not create a burden on other people. For example, you have the right to free speech, but you do not have the right to have an audience. You cannot force other people to listen, as that would violate their rights. The same principle applies to other actual rights. You have the right to keep and bear arms, but you not have the right to have the tax payers buy you a gun.
A 'right' to education would impose a burden on others. We would be compelled to teach you. Or to hire teachers to educate you. Therefore, this cannot be a right. It imposes a burden on other people, and therefore fails the test of being a right. In fact, education is a luxury good. It is a good that people worry about after they have food in their belly, a roof over their head, and enough spare time to educate. It is most certainly not a right.
'free' -- they mean free to the consumer of the education, of course. Not free to the taxpayer. In fact, 'free' public education is the most expensive education that you can buy. School districts are spending $10-12K per student on education. This is far from 'free'.
'quality' -- as the last 100 years have demonstrated, there is not much quality in education. Because the schools are large government run bureaucracies, they lack the incentives to deliver quality goods and services. Therefore, they get fat and inefficient. While Federal spending on schools has skyrocketed into the billions, test scores and literacy continue to decline.
'Public' -- because the schools are public, they are political. All decisions about curriculum, teachers compensation, standards, etc. becomes political decisions. And political decisions are not always based on low costs and efficiency, or even with the best interests of the students in mind.
So we find that almost every word of this fantasy is the opposite of reality.
None of it has any meaning in the real world, or if it does, it has the opposite meaning to what they intend.