I assume that with "the mixins", you mean the ones at
https://monitoring.mixins.dev/ /
https://github.com/monitoring-mixins/docs.
Quote from that document:
"During the experimental phase, we should probably start with a centralized repository that is clearly marked as experimental (and might go away). This enables quick iteration and experimentation with the example bundles, until we get a better idea of what works and what doesn’t. When the example bundle format becomes more settled and people agree on the usefulness of the concept, we should consider hosting the examples in decentralized fashion, together with the exporting components."
So if we think that the overall way of structuring mixins has become relatively stable, it might be time for that second phase. I'm not personally involved enough with the current jsonnet mixins efforts to judge that, but I'm sure others can.
Cheers,
Julius