If you support all 3 formats you should say you support PNM not PBM (PBM is for 2 colours per pixel, literally 1 bit).

If I've written I support PBM, it means exactly what it means - I support PBM for now (P1 and P4, 1 bit per pixel). PGM and PPM support is yet to be done. Not very difficult of course, but takes some time. I guess I should know that PBM is 1 bit per pixel after writing a decoder for it, don't you think?

But well, netpbm.demuxer is supposed to recognize and decompose headers of all the trio (bitmap, graymap and pixmap). So you suggest it should be named "netpnm.demuxer"? Looking at Wikipedia I've found that there is no article for "NetPNM", only in NetPBM article there is a note "Several applications refer to them collectively as the PNM format". The original package is called NetPBM, most of references too. Then I think NetPBM name refers to the set of formats (named separately as PBM, PGM and PPM (there is also PAM, which will be supported to)), and is more recognizable than NetPNM.