https://gitlab.gnome.org/World/gedit/libgedit-gtksourceview/-/compare/299.2.1...299.3.0
https://github.com/gedit-technology/libgedit-gtksourceview/compare/299.0.5...299.2.1
Version scheme is now documented in upstream README.md, which suggests that even 299.x.y can be stable as long as minor version is even.