In the world of computer development, “PR” usually means “Pull Request”, as in a request to pull suggested changes from a member’s repository to the main repository of a software, to apply changes or fixes.
Depending on the platform used (Github, Gitlab, …) this is also known as a “MR” (Merge Request).
So basically, @Alexey is suggesting that any motivated member that has the technical knowledge could submit a Pull Request for adding this new feature, and the Storj team would be happy to review it and include it in the Node software if it matches their quality and security standards