A copy of the current project is saved in the same folder as the original project. The name of the copy is the name of the original followed by a number. If the name of the original ends with a number, that number is increased by 1.
The open project takes the new name and location; the original file remains unchanged.
The open project retains its original name and location, and a copy is created with the new settings but is not opened.
Auto-saved files are saved in the Adobe After Effects Auto-Save folder, which is located in the same folder as the original project file. Auto-saved file names are based on the project name: After Effects adds “auto-save n” (where n is the number of the file in the auto-save series) to the end of the filename. Maximum Project Versions specifies how many versions of each project file you want to save. When the number of versions saved reaches the maximum you specify, the Auto-Save feature overwrites them starting with the oldest file.