I noticed that when archieving a project the fonts used in the project are not archieved. IMHO is a important piece of a project that will go missing if the project will be moved between different pc and overtime. Please add the fonts to the archieving
Kdenlive only uses the fonts that are installed. The project file only contains a reference to the font. In order to use the same font you need to have it installed on the other system, too. I don't know whether you can include a font file just like that. AFAIK, font files need to have special format to be installed on a system, and you cannot just copy and paste an installed font. In addition, depending on the OS you may need special privileges to install a font. When opening a project file that needs a font that is not installed, Kdenlive issues a warning about the missing font, and you can decide whether to use a different font or a placeholder. Then install the missing font afterwards.