12b36d5d_ebug_Preferences___FirebugWiki__Option
[Description] Hidden columns inside the Net Panel [Valid Values] netHrefCol, netTimeCol, netSizeCol, netDomainCol, netStatusCol [Default] "" [UI Equivalents] Net Panel->Request List header context menu->Columns [Option] 
net.hiddenColumns
Firebug Preferences - FirebugWiki