Normally a valid CCF constituent will have the CATEGORY attribute set to XMMCCF. However, it is possible to instruct cifbuild to accept constituents with a different category via the parameter category. For instance, the SOC distributes CCF constituents tuned to the output of the science simulator. These datasets have the CATEGORY attribute set to SCISIMCCF.
The category can also be ignored altogether with the parameter ignorecategory.
If the parameter append is true, then cifbuild appends to the CIF set pointed to by calindexset any other CCF constituent that is not already in that CIF. With this mechanism it is possible to build a CIF incrementally, giving priority to a certain category of constituents (see example 8).