Sorry for not being clear. They are column labels, groupname should be something informative, indicating the provenance of the data.
Perhaps an example would clear things up:
2FOFCWT,PH2FOFCWT would be replace by phenix.refine.F_phi.F and phenix.refine.F_phi.F or perhaps phaser_sol_2.F_phi.F and phaser_sol_2.F_phi.phi and FP, PHIM, FOMM would be perhaps RESOLVE_weighted_Fs.F_phi.F and RESOLVE_weighted_Fs.F_phi.phi. There should be no need (for the user) to consider the weights column, we have seen too many otherwise competent people use double-weighted or unweighted maps (I'm sure you must have experienced that too). These columns can be generated in addition to the current ones of course.
Probably "F_phi.F" in "xxx.F_phi.F" above also should be something informative. For example, it should reflect the map type: 2mFo-DFc 2Fo-Fc 2mFo-DFc (computed with missing Fobs filled with DFc) 2Fo-Fc (computed with missing Fobs filled with DFc) Kick maps Anomalous difference map etc... in some obvious way. Currently, phenix.refine has to output 2mFo-DFc map with labels (2FOFCWT,PH2FOFCWT) simply because this is what Coot will automatically recognize. Looking at (2FOFCWT,PH2FOFCWT) it is absolutely not obvious which map it is (unless you coded it therefore know). However, something like (2mFoDFc, PH2mFoDFc) has the same length as (2FOFCWT,PH2FOFCWT) but much more informative. For kick or missing-Fobs-filled maps, one can simply add a suffix to corresponding map name, for example: (2mFoDFc_fill, PH2mFoDFc_fill) (2mFoDFc_kick, PH2mFoDFc_kick) Pavel.