That's actually intentional, and one of the reasons why our site exists. Every company has different nomenclature for their leveling that doesn't necessarily align with other companies. So we developed a standard as a normalization for all the leveling which you can view here: https://levels.fyi/standard

As a part of this standard, ICB 6 falls under the 'Staff Engineer' standard level (you'll also notice it maps closer to Google and Facebook's Staff levels as well: https://www.levels.fyi/t/software-engineer?compare=Broadcom%...)