Huge thanks to Berni's Snippet.
What does this do?
Depends on what you do with it. However, the only function I'm immediately aware of is suppressing selected ConVar changes from being printed to chat.
Oh? Is that all?
... Are there any commands?
Indeed there are. As a matter of fact, there is only one
<convar> <enabled|disabled> - Whether to display changes of this ConVar to Chat or not.
Can you give an example?
Sure! sm_suppressconvar sm_nextmap enabled
THIS ALREADY EXISTS
Oh. Ok. Sorry! At this present time I'm unaware of any that are not hard coded.