Just a follow-up to my previous post with the reason I believe this additional strain relief is beneficial. Underneath that very cool braided sheath lies a stranded, PVC insulated cat-5E Ethernet cable. It's good that the individual conductors are stranded, since stranded cables usually offer better flexibility than solid conductors. Additionally, the RJ45 terminators have a more flexible and complete connection to stranded wires than solid wire.
However, the cable's PVC outer insulator is susceptible to permanent deformation (stretching) every time the cable is forced to bend sharply near either connector. The additional strain relief afforded by the heat shrink tubing helps to distribute any applied force over a larger area, effectively reducing the potential for damage.
The Neutric etherCON RJ45 connectors do include a small strain relief "boot", but IMHO it is not sufficient for a guitar cable application. For context, most Ethernet patch cables are used to connect devices that do not move around that much, if at all. Thus, the use of PVC is justified for network cabling as it helps keep costs low.
On the other hand, a guitar cable is plugged, unplugged, wrapped, and unwrapped over and over during its lifetime. Additionally, most guitarists are not what I would consider "stationary" objects. Most standard guitar cables use some type of rubber-like insulator that resists permanent deformation, but still utilize heat shrink tubing near each 1/4" jack for added durability.
Again, this is just my opinion and not intended as any type of criticism. Hopefully the community will find my suggestion and explanation useful.