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 YR, 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