A major version of 0 isn’t necessarily any statement regarding the projects maturity, it can also be a hack with semantic versioning. Normally, any change that is not fully backwards compatible requires you to increment the major version, but if the major version is 0, you may only increase the minor version. Because of this, many projects stay at the 0.x.y versions, so they don’t need to release version 2.0.0, 3.0.0, 4.0.0 and so on just because of minor but breaking changes as many users might expect significant new features from that version steps.
A major version of 0 isn’t necessarily any statement regarding the projects maturity, it can also be a hack with semantic versioning. Normally, any change that is not fully backwards compatible requires you to increment the major version, but if the major version is 0, you may only increase the minor version. Because of this, many projects stay at the 0.x.y versions, so they don’t need to release version 2.0.0, 3.0.0, 4.0.0 and so on just because of minor but breaking changes as many users might expect significant new features from that version steps.