RISC-V did the same with its open source ISA project to implement processors. IBM opened its architecture under the OpenPOWER project, but it seemed that there were still some opaque things in this project that had nothing to do with the transparency of RISC-V. But now, this new movement could change things somewhat, and it seems that IBM is moving OpenPOWER under the umbrella of the Linux Foundation.
IBM is the developer of the ISA PPC that can be used by various microarchitectures, including IBM's own. But IBM wanted to go a little further and created OpenPOWER Foundation to offer more open source "pieces" for other contributors to use and contribute. Now it seems that something is cooking, or rather, something is moving and it could be positive for everyone ...
Ken King, the manager of OpenPOWER, says the organization is evolving and they are going to move it under the Linux Foundation. And it seems that they also want to give more facilities and technical foundations of the POWER series to developers and engineers to build on this technology, apart from opening the ISA. POWER ISA implementations are now free and now IBM's IP-based processors can be manufactured in any factory and combined with other hardware products.
But not everything is open, which is why its popularity and reception by the community it was not as good as in the case of RISC-V, despite the fact that some "experts" supported that OpenPOWER would be "the open source processors of the future ..." Perhaps now under the Linux Foundation things change, in fact, IBM sees open source as a major advantage over licensing and control according to King: “The first thing is that we are giving the place of being able to implement what we are licensing, the architecture of the ISA instruction set, so that others can implement it.