Project
A public catalog for versioned RISC-V ISA extension packages.
Last updated: August 2026
ExtenSilica is a free, public registry for RISC-V ISA extensions. It gives maintainers one place to publish versioned packages and gives users one place to discover, inspect, install, and cite them.
The open .xsil format carries identity, upstream provenance, ISA requirements, encodings, dependencies, documentation, checksums, and optional simulator, toolchain, RTL, test, example, or hardware artifacts. ExtenSilica stores and indexes that package metadata without making claims beyond what the archive declares.
The platform is operated by ExtenSilica as interim technical steward. ExtenSilica is an independent project and is not affiliated with RISC-V International.
For stewardship boundaries, funding policy, and XSIL governance tokens, see Governance and Contributing.
São Paulo, Brazil
The registry and website are built and maintained from São Paulo. Community contributors and Extension maintainers participate from many countries; the registry itself is global and not limited to a single jurisdiction.