Hello, I cannot install rqt-tree with ros dashing.

According to here it should be available for dashing : https://index.ros.org/p/rqt_tf_tree/github-ros-visualization-rqt_tf_tree/#dashing

But it seems that it's not in the official repo.

$ sudo apt install ros-dashing-rqt-tf-tree  
E: Unable to locate package ros-dashing-rqt-tf-tree

How can I get it ? Thanks !