Manufacturer prefixes
The first characters usually identify the product family and the manufacturer's catalogue system. They are not standardised across companies, so the prefix tells you where to look rather than what the cable is.
Size and count
Numbers in the middle encode AWG or kcmil and conductor count, often with a slash: 12/2 and 12/3 for branch cable, 4/0 for a single large conductor.
Colour and packaging suffixes
Trailing characters frequently denote jacket colour, packaging length or a special option. A suffix difference can mean a different colour of the same construction.
When to stop decoding
If the print is legible, trust the print over the part number. Part numbers are useful when the print is gone and the tag survives.