If you are looking for an open source stacked PRs CLI, you can look into av CLI (https://github.com/aviator-co/av). Unfortunately this also only works with GitHub, but it should be possible to add support for any Git-based platform.
Disclaimer: I'm the founder of Aviator who supports the av CLI. It's a free tool to manage stacked PRs.
Disclaimer: I'm the founder of Aviator who supports the av CLI. It's a free tool to manage stacked PRs.