Ok not sure how such a post got so many upvotes...

She has not really much to do with open source or at least that's not verifiable anywhere:

• no recent activity on GitHub
• A total of 5 commits on Codeberg.... about designing an USB stick

Also she was active on Mastodon 3 days ago.

This person most likely is spontaneously disconnected from the net. Maybe the internet is down at her location because lightning fried the router, maybe she fell down the stairs and is in hospital, maybe she's on vacation or - after having read through the about site - got some mental help, because not blocking and posting about people that send you creepy text messages to give them a wider platform is itself weird...

Who knows?

But starting a search on all social media will likely not bring them back either.

Maybe contact their family or other friends or visit them, I think that would be a lot more productive.