New retainer material feature in 6.3?

[Nezerius]

Since the unofficial translation has Yoshi-P's answer as:
"Y "There is one more update to your retainers inventory management but it is too difficult to put into text and words so I will show you during the next PLL, I think people who have a lot of materials stored will be really happy about this one""
It's probably not as simple as being able to craft using materials from your retainer.

Perhaps it's a material storage with split into tabs for each expansion.

[Reimmi]

Since the unofficial translation has Yoshi-P's answer as:
"Y "There is one more update to your retainers inventory management but it is too difficult to put into text and words so I will show you during the next PLL, I think people who have a lot of materials stored will be really happy about this one""
It's probably not as simple as being able to craft using materials from your retainer.

Perhaps it's a material storage with split into tabs for each expansion.

Could always be both.
New, seperate material storage and the ability to use them from said storage