If you mean "write code for", then honestly I make very few code contributions. In the 00s, my employer was suspicious of developers contributing to open source, to the point of banning it contractually. I've since changed employer, but I have a legacy of that early experience.
On the other hand, I contribute to open source projects in many ways - I give money to many projects I use, attend meetups, give presentations at conferences, coach people, write answers on StackOverflow.
If you mean "write code for", then honestly I make very few code contributions. In the 00s, my employer was suspicious of developers contributing to open source, to the point of banning it contractually. I've since changed employer, but I have a legacy of that early experience.
On the other hand, I contribute to open source projects in many ways - I give money to many projects I use, attend meetups, give presentations at conferences, coach people, write answers on StackOverflow.