As of 3.0, documents in system.profile now include a new "locks" field. This replaces the "lockStats" field, which has been removed. The "Database Profiler Output" reference page should be updated to reflect this change.

Note also that the new "locks" subdocument has a different format from the old "lockStats" subdocument.

I also suggest that b5fb56a4 be reverted as part of this ticket, as SERVER-16020 (the change that prompted the creation of the DOCS-4447) was later reverted by 8f83ff233.