In the new files, Tez2 found a hint that developers are working on a mission editor for GTA Online, which will be available to all players. In light of the possibility that themed DLC releases might cease in the coming years, this will be a breath of fresh air for the community.
A file named public_mission_creator has already been added, but it is currently empty. It is possible that the mission editor will be introduced with one of the upcoming DLCs (the next one is scheduled for release in December).
Source: gta.com.ua