There are several options in boot.properties that are not documented, including:
% Indirectly doc'd via the default encryption keys
Some of these options are implicitly doc'd in the comments to the file. But I don't think the comments are sufficient, e.g. I think we should discuss opeindm.bonecp.statistics.enabled in the discussion of the BoneCP connection pool library, in this JDBC section
As boot.properties is an important part of the IDM configuration process, I think it's important to explicitly document each feature in this file.