Yes, I meant that lots of proprietary software links with and relies on FLOSS components.

E.g. I open Slack (a random pick - it's open on my desktop right now), a proprietary software app. And in the "about" section there's a huge list of FLOSS libraries they use: https://slack.com/libs/desktop

Moreover, I'd say, every website out there (and web is a giant niche) uses lots of FLOSS components.

And for GitHub contributions, I meant that once in many years there happens to be a library that's out of date but otherwise useful, or lacks some nice feature.