Not sure what model year you own, as the sigs never show on Tap-A-Talk.....
However, I believe what you're referencing is part of the vacuum line for the brake system.
Check the pic located within the link below.....
https://www.tascaparts.com/oem-parts/ford-vacuum-hose-dg1z9c490b/?c=Zz1icmFrZXMmcz1oeWRyYXVsaWMtc3lzdGVtJmk9S0QwOTI5MTUmcj0xMyZhPWZvcmQmbz10YXVydXMmeT0yMDEzJnQ9c2hvJmU9My01bC12Ni1nYXM%3D
LMK if I was close and/or right. I searched up a 2013 for 'ya.