I contributed code to the following "major" open-source projects:
Ruby language: I had commit-rights in the past. My XMP-RPC for Ruby library was once part of the stdlib. I am no longer active in the Ruby community.
DragonFly BSD: This is a fork of FreeBSD 4. I am a rather sporadic committer. You can see my commits here. Most of my more recent commits were related to making DragonFly run on my hardware or were Rust-related.
Rust language: Rust is a modern, safe systems programming language which I am using since 2012. I am maintaining the DragonFly port of the compiler and related libraries, and issued myriads of pull-requests. You can see some of my commits here.
Read about my language history.