https://github.com/free-audio/clap
Bitwig has it integrated experimentally, and I believe the REAPER devs have said they aren't opposed to adding it in the future.
Minor correction: CLAP was not made by U-he, but by someone who works for Bitwig and maintains VST2 builds of U-he synths for Linux.
Schwaa has basic support of CLAP in Reaper at the very least in his own branch. I believe both Reaper and Bitwig devs are waiting for CLAP 1.0 to be announced to make all this official. Which is not too far away.
> CLAP was not made by U-he, but by someone who works for Bitwig and maintains VST2 builds of U-he synths for Linux.