I am experimenting with FLL Band-Edge block. It is using and creates positive and negative band edge filters. According documentation, in C++, there is method print_taps(). How to get filter taps created by FLL Band-Edge block in GNU Radio Companion?
The fll_band_edge_cc class has no interface for getting the taps. Sorry. You can, if you need that, always open a PR against the main branch on https://github.com/gnuradio/gnuradio ; or request a feature.
What I'd recommend, however, is just looking at the source code of the filter design process for the two band edge filters, in fll_band_edge_cc_impl. There's not too much magic in here, and I'm not sure these would be the filter taps that harris would recommend using for an FLL.