Segger is available as a plug-in to Chimera, and it works with Chimera versions 1.3 and 1.4. It is written mostly in Python, which works on any platform, but it makes use of a binary written in C++; compiled version are available on most platforms.
The latest version is 1.2.
Please note that version 1.2 will not be able to read _regions files from previous versions. A slight change to the file format had to be made to support saving of regions groups. As a result, grouping and ungrouping is now possible even on saved and reloaded _region files.