[0xmohit]

Kenton Varda (the author of Cap'n Proto), was the primary author of Protocol Buffers version 2.

Quoting from https://capnproto.org/index.html

  Because it’s easy to pick on myself. :) I, Kenton Varda, was
  the primary author of Protocol Buffers version 2, which is the
  version that Google released open source. Cap’n Proto is the
  result of years of experience working on Protobufs, listening
  to user feedback, and thinking about how things could be done
  better.

[euyyn]

To be completely fair, Protobus v3 is also the result of years of experience working on Protobufs, listening to user feedback, and thinking about how things could be done better :)