A swage terminal is a stainless tube pressed onto the end of a rigging wire under huge pressure, so the metal grips the strands. At the bottom of a shroud it carries the eye or stud for the turnbuckle. At the top it ends in the fitting that goes into the mast.
The pressing leaves stress in the metal, and lower swages sit where water runs down the wire and stays. Over years, cracks start along the barrel. They're often fine enough to miss without a magnifier.
What a surveyor checks
Every terminal the surveyor can reach, with a magnifier. SAIL describes the signs: a fine line along the barrel, usually lengthwise, and broken strands where the wire enters. Dye penetrant shows cracks too fine to see. The top terminals need binoculars or a climb, and the report says which were seen. The rigging's age from records goes in next to it.
In the report
"Port lower shroud, lower swage terminal, hairline crack along the barrel about 15 mm long. Replace the shroud before the boat is sailed." A cracked terminal is a safety finding. See cracked swage terminals.