SoFieldConverter(3) on Linux
The text 49eded781e4b, as Debian 6.0 (Squeeze) shipped it.
The SoFieldConverter class is the abstract base class for field converters. When fields of different types are attempted connected, the Coin library tries to find a field converter class which can be inserted between them, acting as a filter converting values from the master field to values matching the type of the slave field.