Pinning a replay could work like this:
Whenever you do /pinreplay, the replay will automatically stay at the top of your replay list until you unpin it. Either by doing /unpinreplay or clicking on the pinned replay and selecting “Unpin Replay”
This would be very useful for content creators and even regular players if they see something in a game but still want to keep playing. People also forget things, like if they have a replay ID copied but they forget to share it.