Registry Explorer has a plugin for this.
#PS to decode UTF8 strings
gp HKCU:\Software\7-Zip\FM *History|Select *History|%{ $_.PSObject.Properties | %{ $_.Name ; [Text.Encoding]::ASCII.GetString( [Text.Encoding]::UTF8.GetBytes( $_.Value , 0 , $_.Value.Length )) }}
#Query registry for history string
reg query HKU\{SID}\Software\7-Zip\ /s /f History
