This is a config framework, with its main purpose being to replace defaults with more optimal values, providing large performance gains with minimal impacts to visual quality and general improvements towards everything else.
It is very customizable and will under most circumstances appeal to your personal preferences.
If you've never used configs by others (or already cleaned), ignore this.
Open Steam, go to your Library, right click 'Team Fortress 2', click on Properties.
Click on Local Files, then 'Browse Local Files'.
Open the tf folder, then delete the cfg folder.
This will reset any settings you have changed within Team Fortress 2.
Click on 'Verify Integrity of Game Files' in Steam and wait, this is in the same tab as 'Browse Local Files', there will no longer be conflicts after Steam is done verifying.
Used an older version of my config? It's as simple as removing the TF2 folder in tf/custom, make sure to reconfigure the autoexec after installing again!
Download the latest version from: https://github.com/source-engine/optimizations/releases/latest
Extract the downloaded zip.
Open the extracted folder and copy the folder TF2.
Open Steam, go to your Library, right click 'Team Fortress 2', click on Properties.
Click on Updates, then remove the check from 'Enable Steam Cloud synchronization for Team Fortress 2'.
Click on Local Files, then 'Browse Local Files'.
Open the tf folder, then open the custom folder.
Paste TF2 into the custom folder you have open.
Open the TF2 folder, then open the cfg folder.
Right click 'autoexec.cfg' and edit with Notepad++
Download from: https://notepad-plus-plus.org
You can then personalize to take full advantage of the config framework as intended!
Make sure your drivers are 388.31, they seem to work very nicely and have no stutter/crashing issues! :D