Flexbox section 9.9.1 "Flex Container Intrinsic Main Sizes" starts out like so:
- For each flex item, subtract its outer flex base size from its max-content contribution size.
Here, "max-content contribution size" is linked to the generic text about max-content contributions in CSS3-Sizing. This isn't particularly helpful in hinting at what quantity should actually be used in the arithmetic described here.
Instead, that term should link to Flexbox section 9.9.3 "Flex Item Intrinsic Size Contributions" which is where we actually mathematically define what the contribution should be for a flex item.