Hi, I am Ryan and I can assist you with this.
your .prproj files are just saved states from the adobe premier program. They don't actually contain any video themselves. They are only for Adobe Premier.
Pretty much every video editor does the same thing. When you save your video in the editor, it saves a project file which contains all the edits you have done, which transitions and filters you applied, etc...
The video is still in the original video files untouched. Its not until you "render" the video that it is output in finished form in the format you chose.
Were you able to see the text i put in before you were in the chat session?