TCE in the titles refers to the :tce directory", which stands for "Tiny Core Extensions", and the boot option used to specify such. The directory name is not tcz nor is the boot option.
Appbrowser Install does not necessarily installs to ram, it depends on mode, if a persistent local is being used then it installs onto the disk where specified by the "local" boot option for PPI compatible extensions. If using traditional (scatter) installation the install option, installs as a traditional distro would onto the disk where the filesystem was installed, again no ram involved.