Master Cylinder?

The last couple days I noticed my brakes are softer than normal. The brake pedal is now going down below the gas pedal but doesn't feel like when I've had air in the brakes from repairs in the past. The fluid was low but I didn't see any obvious major leaks but did see a tiny bit of old dry looking fluid on a fitting below the MC. I did have to add quite a bit of fluid to top off the reservoir.

I'm planning on getting a master cylinder but this started a day or so after having to hit the brakes really hard. Could that have done in a MC on its last leg? Is there something else that could've happened causing them to be soft now. I'm overdue for a fluid change and brake lines.

Probably not related but my ABS fuse is pulled. It was doing the typical DI thing of kicking in when it shouldn't and having no brakes. At the beginning of the summer I replaced the front sensors (fixed it the time before) and rolled out into the street when backing out of the garage right after so I pulled the fuse and haven't looked at them since. I think it gave me a code for a shuttle valve(?) but I thought this was just from having the fuse pulled.

Thanks

I got a better look today and there’s quite a bit of fluid on the fitting below the master cylinder so I think it must be leaking. I didn’t check the caliper pistons after seeing that but I don’t think it would be a problem since rust usually isn’t an issue here.