Premiere Elements places the new files into a folder with a name that starts with either Trimmed, if you chose Archive Project, or Copied, if you chose Copy Project.

About archived projects

The Project Archiver copies your project and its media to a folder for further editing or storage. You can use it to prepare an incomplete project for editing on another computer, to collect into one folder copies of media that may be located in several folders or drives, or to trim the media in a completed project down to only the parts you used before saving the project to an archive. The Project Archiver has two options, Archive Project and Copy Project. Since Copy Project does not trim the project, it often results in a folder containing more, and larger, files than does Archive Project.

Creates a folder containing a new project file, and a new clip for each clip used in the original Quick view timeline or Expert view timeline at its edited length. The trimmed project includes up to 30 frames of extra footage, called handles, before the In point and after the Out point of each trimmed clip for minor adjustments you may want to make after archiving the project. A trimmed project excludes any rendered previews and audio previews (conformed audio), as well as any unused media. Premiere Elements automatically creates new audio previews (but not rendered previews) when you open the trimmed project. Clips in a trimmed project are renamed so that their filenames match the project filename. Use this option to ready a completed project for storage, before you remove it from your hard disk.
Note: Project Archiver retains any effect keyframes and clip markers that exist beyond the In and Out points of a trimmed clip.

Creates a folder containing a new project file, and full copies of all the media that appear in the Project Assets panel in the original project, whether or not any of them were used in the Quick view timeline or the Expert view timeline. Unlike Archive Project, Copy Project does save all rendered preview files. Use this option to aggregate copies of all files belonging to a project into a single folder. This easily can be transferred to another computer, or opened for further editing at a later time.
Tip: Archived project folders can be large, so archiving to a portable hard drive is recommended when you intend to transfer a project between computers. Using a disc-burning program, you can also burn trimmed or copied project folders to DVDs for archiving or transfer to other computers.