Are you thinking of Fractal (a multiplatform Matrix client)? https://matrix.org/ecosystem/clients/fractal/

Or possibly Stoat, which has been mentioned a bit (not starting with an F, but sounds closer to Flow). https://stoat.chat/

Ah, I see the problem, you’re not waiting long enough.

Technically, you’re among the stars before you even start.

If you wait long enough, the moon will come to you.