I think you mean this one: http://blog.erratasec.com/2014/07/validating-xkeyscore-code....

Thanks, clipboard wasn't syncing properly.

that article: "The filename xkeyscorerules100.txt is implausible. Source files do not end in ".txt" and the term "rules" is an odd choice."

Looks to me like a typical sample config file that you rename xkeyscorerules100 after editing just like how you would create /etc/udev/rules.d/51-android.rules or SELinux custom module policy before compiling.

Yeah, there are so many reasons it could have a .txt extension the criticism is not plausible. The first thing I thought of was, somebody nontechnical in the reporting pipeline changed the extension to .txt so it would open automatically in a text editor on their OS. Or, they pasted the contents in notepad and saved it, which would automatically append the .txt extension.