"Reset" argument for AI functions
This is vanilla but AFAIK not documented anywhere. I've tested it with AiTravel and assume it applies similarly with eg AiActivate, AiFollow, AiFollowCell, AiEscort, AiEscortCell... AiActivate doesn't work if that parameter is used. AiWander doesn't do anything different with it, it resets anyway.
GetAiPackageDone normally only returns 1 for one frame, when the Ai function has been executed (AiTravel: once the NPC reaches its destination). The last argument of Ai functions (AiTravel: 4th argument) is optional. If it is given (0 or 1 doesn't matter), once AiTravel is executed, GetAiPackageDone will NOT reset to 0 until a new Ai command is called on that NPC. In cells without pathgrids, AiTravel will start again and keep trying to reach its target when it collides with statics (without the parameter it just stops).
The point of this is that scripted Ai sequences won't break if the "package done" frame is skipped for any reason - in vanilla it's skipped if the PC waits/rests during the execution of AiTravel. Somewhat related: https://bugs.openmw.org/issues/1464
(RM-1465 from redmine: created on 2014-06-11 by rot tor, , duplicates #2342 (closed))