Currently, Bitbucket supports downgrading git requests to v1 but it doesn't support git v2 itself. It would be beneficial to add v2 support as it would open the door to adding additional features like partial clones and more, in addition to the performance improvements.

Update: Thu 08, Aug 2024

Growing demand for large monorepo scale repositories resulted in Bitbucket undertaking performance improvements across the service. Supporting git v2 protocol allows smart clients to reduce the amount of data served by hosting and benefits both our users and the hosting. We have enabled support for git v2 protocol for both git over HTTPs and SSH.