Hi,
These are Inventory Part Characteristics that are connected to the Manufactured Inventory Parts that you are scheduling in APB. Typically, the characteristics are used during the Sequencing of a work center resource to minimise setup and change over times of the shop order operations based on the characteristic value (e.g., color).
Take a look at this previous post which should give you some idea of how Inventory Part Characteristics are set up "Smart" Scheduling | IFS Community
See also this APB Setup Guide where ‘Sequence Shop Orders by Characteristics’ is described on Page 77-81 APB - Advanced Planning Board | IFS Community
I hope this helps.