ehm, Dump() just shows it all very verbosely.. but it IS a cheap utility. Cheaper than any alternative, at least.

All you're seeing is that $x is a reference (RV 0x1bd1cc0) to the lvalue object (PVLV 0x1bc3388) which points to the string you've taken a substring of (PV 0x1bcd490), and the lvalue object has one piece of magic to point to the functions implementing extraction and replacement of substrings. That's obviously about as simple as it can get.

Just for fun, dump an array containing the relevant info: Dump [\'the quick brown fox', 10, 5];