This is the most stable official Grimoire in the Codex. This grimoire contains spells that are known to work together with each other. It isn't updated that frequently and isn't up to date. However this does not guarantee the programs themselves won't be buggy and unstable as the actual software belongs to the author(s). This just makes sure that it won't disable or conflict with another spell in the grimoire.
Note: this grimoire is the default grimoire on a newly installed system.