Took some pics, but can't upload because file is too big and the computer I am at doesn't have anything to resize pics. However, looking at the inside of the frame rail, there are three hard lines: bottom one is steel brake line, middle is pressurized fuel line (i think stainless), and top line is the one in question. It is steel and is routed over the top of the top spring perch on the left rear tire and goes to the fuel tank.
1998 TJ Sport, 4.0L - 5 spd -Suffering from frame rot
2006 Grand Cherokee Overland (5.7L HEMI)
HEMI Club Member #53
2003 M-B C240 4matic