Doesn’t explain it all.

Presumably Stripe owned it before, now they don’t… or own some smaller portion (since it’s stated they’re an investor)

Likely either founders bought back a portion of the company, or Stripe relinquished ownership out of goodwill. Perhaps it was worth very little, I’m not familiar with it

Maybe Stripe gave it back partly out of goodwill. For Stripe to do something without the brothers would be to spend a lot to reinvent it anew. Not worth the effort probably. Indiehackers always struck me as pretty small for something like Stripe to own. As if Microsoft had the one single coffee shop somewhere in Manitoba.