# File Extensions

This puzzle is part of the Monthly Topic Challenge #1: Restricted Title: xkcd 1xxx

I’ve been tasked with auditing a certain computer. I was advised that the owner of the computer might have deleted some evidence before handing it over. Upon inspecting the file system, I found to my relief that no files had been recently deleted, and all their contents and time stamps were intact. But I noticed something very odd: all of the file extensions had been removed. Here is the file listing of the disk:

audio/homophonescompressed.___              02:17:05
audio/homophonesrawrecording.___            03:13:00
emus/wine/system32/recyclebin.___           15:04:10
emus/wine/system32/spinninghourglass.___    19:16:07
puzzling/prooffermatslast.___               09:21:20
puzzling/theultimatechessstrategy.___       12:00:06
scripts/bash/wordmatcher.__                 22:01:00
scripts/python/anagramer.__                 11:14:00
scripts/typescript/rot13.__                 18:08:00


Who am I and what has the owner of this computer been up to?

Who am I and what has the owner of this computer been up to?

You are working for a fiscal authority and are trying to find evidence of tax evasion.

The file extensions ...

... can be derived from the nature of the files. They are:

.oga: an OGG Audio file
.wav: an uncompressed sound file
.ico: an icon
.ani: an animated cursor
.tex: a TeX source file for typesetting formulas
.pgn: the portable game notation for chess games
.sh: a shell script
.py: a Python script
.ts: a typescript source file

The timestamps ...

... have the curious property that each number from 1 to 22 appears only once, either as hour, minute or second. They probably represent a kind of order. There's also a correspondence between the three letters of the file extension to the three numbers (hh:mm:ss) in the timestamp. (For the files with two-letter extensions, the seconds are zero.)

The letters from the extensions and the hh:mm:ss numbers can be seen as sequences. The first letters are O, G, A, W, A, V, …; the first numbers are 02, 17, 05, 03, 13, 00, …

Now create 22 empty slots. Put the first letter O into slot 02; put the G in slot 17 and so on. (If the number is 00, do nothing.) A message is spelled out:

HOW CAN I STOP PAYING TAXES