db.foo.explain().
.aggregate(...) - explain an aggregation operation
.count(...) - explain a count operation
.find(...) - get an explainable query
.group(...) - explain a group operation
.remove(...) - explain a remove operation
.update(...) - explain an update operation
Explainable collection methods
.getCollection()
.getVerbosity()
.setVerbosity(verbosity)
...

Note the ability to chain
db.foo.explain().find()
Explain query methods
.finish() - sends explain command to the server and returns the result
.forEach(func) - apply a function to the explain results
.hasNext() - whether this explain query still has a result to retrieve
.next() - alias for .finish()

Explain query modifiers
.addOption
.batchSize
...