Pressing clutch when starting

[Archerfish]

2. Some cars have clutch safety switch, kailangan talagang ipress ang clutch para mastart.

I experienced this with my brother's car. I was wondering why it wouldn't start until he told me that I needed to depress the clutch pedal. He also showed me that it has an indicator.

I'm interested with this, why require the clutch pedal to be depressed before starting?