The MIF and RTF summarizers work by first converting into SGML and then using the Harvest SGML summarizer. The SGML conversion step is performed using a commercial software package (and DTD) called ``Rainbow'', which was developed by Electronic Book Technologies. Since converting these formats to SGML is an ``up conversion'', the translation process is necessarily imperfect. However, the Rainbow software works quite well, and we appreciate EBT's making this software freely available to the Internet community. (Please note that we are redistributing the EBT code and DTD as per their copyright restrictions; we have included a copy of EBT's copyright file in $HARVEST_HOME/components/gatherer/Rainbow/copyrite.txt).
Note that at present EBT only makes executable code available for DOS, SunOS, Solaris, HP-UX, and AIX. Therefore, at present we only provide bundled distributions of the code for SunOS and Solaris (the subset of the above platforms on which we currently support Harvest).
More information on Rainbow is also available.