We've started implementing one here as part of the "Meli" Android App project: https://github.com/p2panda/meli/ - as soon as we're happy with the API we would factor it out in a separate repository and publish it!
Thank you for this! We've heard that feedback from other people as well and totally agree. It's true that it is hard to explain what p2panda really is: It is three things at the same time: 1. a protocol specification 2. a reference implementation and 3. an SDK. We can do better at separating these worlds, maybe by giving it different names or a better website. End of our current funding period we dedicated some time for an overhaul.
Check out our section on "Operations", this is the data type we've built on top of the append-only log structure for multi-writer and conflict free data editing: https://p2panda.org/learn/operations
We're using our own CRDT called "Operations" giving us multi-writer conflict-free editing. It's a simple key/value map with a last-write win rule while we keep some sort of vector clock for every write to understand what every peer has seen when they updated the Document.
This might be limiting for some cases, though so far we could model many applications already with such simple CRDT. It is also possible to add your own or already existing CRDT frameworks on top of p2panda.
Yes, it's been a pleasure to work with OpenMLS, they consulted us with the integration into p2panda! As mentioned in my other comment: while most low-level parts have already been written, we still need to work on our high-level APIs, which should allow for easy integration of data encryption when using our SDKs. We aim at doing this in our next funding period.
Oh wow, we didn't expect p2panda to pop up here (I'm adz, one of the core contributors). Let us know if you have any questions :-)
This week we're wrapping up a long development phase for a new "aquadoggo" version (https://github.com/p2panda/aquadoggo/) - our p2panda node reference implementation. The release will come with a dynamic GraphQL query (filtering, cursor pagination, text search and ordering), blob support, a better configuration interface and a full p2p networking stack (QUIC) with NAT traversal techniques and relays based on libp2p.
Next steps in our current funding period is a showcase app for Android (built with Flutter and Rust FFI bindings from our core libraries), a bee sighting database for scientists in the Brazilian Amazon (in collaboration with https://www.meli-bees.org/).
Further down the lane we're continuing our integration of MLS - as some high-level APIs are still missing - and a capability system. We're definitely not out of ideas yet!