Quick Question - Gen 5 - M/T Clutch

[roushians]

Hey,
My Clutch pedal is acting up. Use to engage at the top of the pedal, now sometimes sticks to floor and now engages right at bottom of pedal, and just got worse this morning as i couldn't disengage clutch to shift.

Slave cylinder looks fine. Master has no leaks but noticed a round rubber disc floating in the fluid in the resevoir. No idea whether this disc is part of the Master Cylinder's resevoir or whether it's supposed to be part of the resevoir's lid. I attempted to remove it using paper towel while parked last night to check it out, and noticed the fluid is super funky underneath this mystery rubber disc. It's sludgy black as compared to the top outside around where it floats where a little different.

So ya, can someone please help me identify this black rubber disc? I'm praying that this has contaminated the fluid causing my problems and that it's not my pressure plate which would be a disaster.

Can someone with a 5th gen quickly take a look at the underside of their Master Cylinder's resevoir lid please and tell me what they see?
Thank you!

[roushians]

LOL, ok I now know that rubber disc is a 'float' and is supposed to be there.
I think I will try and purchase a new one, i think mine is disintegrating and contaminating the fluid