Cxyrtyx

It's a file used by archive.exe to display the original names of the files in the .bsa. It is not necessary for using the mod. Here's a comparison of opening the Unofficial Dawnguard Patch.bsa with and without its .bsl file. http://imgur.com/a/EAeD4 With .bsl http://i.imgur.com/0Dmtg4W.png Without .bsl http://i.imgur.com/rIBR4nb.png