[1] IronDoc febase.h <http://www.treedragon.com/ged/irondoc/febase.htm#fe_box> で使われている媒体型。
[3] 例:
Content-Type: x-ferrum-menu/cell ; seq=x-ferrum-hot-uids Content-transfer-encoding: x-ferrum-uids
Content-Type: x-ferrum-menu/prop ; seq=x-ferrum-hot-uids Content-transfer-encoding: x-ferrum-uids
Content-Type: x-ferrum-menu/map ; seq=x-ferrum-uids Content-transfer-encoding: x-ferrum-uids
[2] 姉妹媒体型 : x-ferrum-head