Dark brown fluid leaking in footwell

[2002 freebie se]

I've been noticing some liquid soaking my carpet on the driver's side. Upon closer inspection I see it's some brownish colored stuff that looks like its dripping from the yellow circled area of this round unit (see photos) behind my console stack, draining down under the carpet. Does anyone know what this is, and how I can go about taking care of this leaking problem?Do you know if this circular unit is possibly a fan housing for the A/C? I've heard before that the A/C can leak into the cabin. But it doesn't really seem like any liquid from any A/C I've ever seen. Thanks in advance for any suggestions and advice.

[2002 freebie se]

Turns out the water leaking in is coolant. Apparently it mixed in with existing dirt in the carpet and looked brown to me, but some of it pooled on the actual vinyl part of the mat and I can see its obviously green. I've seen where this issue can be remedied by replacing an o-ring, rather than the very expensive heater core replacement this usually signifies.

Has anyone heard of this? If anyone has any suggestions here, I'd certainly appreciate it.

Thanks in advance.