I write a lot of my own software and open source it. And very few of those projects ever have/get any contributions from anyone else. In fact, most of the recent ones literally only have one commit out on Gitlab. And it’s pretty rare that I contribute to existing open source projects.

Many years ago, I contributed as part of my job a fair amount to a some WYSIWYG documentation writing web app associated with the Gentoo project. I think that web app is long-since dead and gone. (Not my fault, I promise. Lol.)

Since then, nothing concrete I can think of.