Tmcj4f.ini
Secret .ini file originally found in the Tiberian Sun CDs, contains easter eggs - infantry and unit types from Tiberian Sun with different weapons and names of the Westwood development team. Activated by typing "THETEAM" in the startup screen.
A former Westwood programmer Denzil Long has stated he is the author of this easter egg and clarified the cryptic filename to be an abbreviation of "Totally Cool Mission Just 4 Fun" (with a typo, no less).
(Source)
When activated, this file is loaded after the real rules and treated like an additional rules file, but only for skirmish (not singleplayer campaigns and not multiplay) games.
Bugs/Side-Effects/Unexpected Limitations
In Yuri's Revenge, this can cause pre placed buildings on the map to lose their working animations, such as the national flag with only flagpoles left, and the radar at the tech airport stopping to swing. etc
Since this is not read and used in the early stage of game launch, it has similar issues as the map's built-in ini and MP Mode ini, such as being unable to adjust countries or change the support range of PrismSupportBeam.