I guess you are referring to the yellow/brown in the trough across the centre. Looks like diesel fuel.
Easy way to tell, dip a finger, or a cotton bud in it and smell it. (Don't taste it) Does it smell like the pot of oil you keep for top-ups, or like the fuel when filling the tank.
The pipe highlighted is the spill return pipe. This is a low pressure pipe, so less risk when disconnecting or replacing all or part of it.
The fuel is delivered at very high pressure, and more than is needed to ensure availability. Excess 'spills' back to the tank, or into the supply line, via the low pressure spill pipework.
Wrap a rag around it to catch spillage and prevent squirting into your eyes, and remove the pipes carefully to inspect for damage or cracking. Replace any that need it.
If not sourcing Fiat parts, ensure that any pipes used are fit for fuel use. Should be available reasonably easily.
When fixed, mop up the leakage as best you can, to prevent nasty smells and reduce the fire risk.