Short answer nothing, in R12 its still there and serves as the processing table for budgetary control processing.

Whats different in R12

• the source data from gl_bc_packets now comes from SLA, instead of directly from the calling products (eg AP, PO)
• the data from gl_bc_packets does NOT go to GL, the SLA journal goes to GL 
• the processing unit is now event_id (not packet_id)