This device is a transient voltage suppressor for USB D+ and D- signals. It protects the device from static voltages that may develop when inserting or removing USB devices to connectors.

The four diodes (on side) act as clamping diodes that conduct to suppress ESD.

This or similar device can be found in this Semtech catalog

It's a flexible connection of some kind. In this drawing, it is likely to represent a trailing or reeling cable (I will explain this a bit more below.)

Supporting my claim - from AS1102.3 Graphical symbols for electrotechnical documentation - Part 103: Conductors and connecting devices, we have:

Note AS1102 is based on IEC 617 Graphical symbols for diagrams.

Contrast the symbol for a jumper ("connecting link"), also from AS1102.3, and a fuse, from AS1102.7.

What's a trailing cable?

A trailing or reeling cable is used to power mobile equipment, i.e. a mobile drilling rig, or mobile substation.

In this application, I think the 'sub-sea' transformer is in some kind of waterproof container, connected to the surface supply by trailing cables. Flexibility is required for the transformer to be moved around, or to move with the water currents.

Note that trailing cables are a special breed, not like regular cables. See Olex catalogue for trailing and reeling cables. Generally these cables are much more flexible than normal cables, are designed to withstand cars running over them, etc. There are also special protection features to detect if the cable has been damaged - these aren't required for normal cables which spend most of their life living in a protected environment, i.e. conduits.