Ignoring the self-contradiction in the title, is there documentation for packages such as Algebra, which probably contains lots of useful functions? (The only one whose functionality I'm familiar with from other question is MatrixPowerMod).
Also, is there a list of other such undocumented packages anywhere?
Finally, at least for Algebra, how can I load it? The usual Needs["Algebra`"] fails.
I assume these things are undocumented because Wolfram doesn't promise to support them in future releases.


FindGraphCommunities. The problem that this function solves is not very well defined mathematically, so one can't practically draw conclusions from the result of the function without knowing what it did precisely. The methods are not documented. I can make a guess at what they might do, but important implementation details are still a mystery. Furthermore, the individual methods do generate useful (sometimes critical) ancillary data, which the main function doesn't expose. $\endgroup$