@lxo @freemo because all users still have to impose this requirement on all the people that copy their software.😂

that's not the way dual- or multi-licensing works. I realize that's not exactly what's being suggested, but I'm still having trouble understanding how this could possibly work.
either (a) the recipients get to choose whichever licenses they wish from the set, in which case this is no different from dual licensing and effectively equivalent to going CC0/WPDD/WTFYW (that are presumably contained in the set), (b) recipients accept a single license that encompasses all of the licenses, i.e., all of the permissions and applicable conditions and requirements, but further constrained in some way (e.g. some copyleft-like property that requires passing on all the bundle to downstream recipients) that would render itself incompatible with strong copylefts that do not allow any such further requirements

@lxo "that's not the way dual- or multi-licensing works." Of course, but as you say: "I realize that's not exactly what's being suggested"... I was talking about something that was not dual-licensing, and is instead something totally different from that.

so, not dual licensing, it's more like something totally different, that I also mentioned and that also doesn't work, say a license with additional restrictions on top of those of copyleft licenses? or is it something else?